Xeelee Sequence Novella Collection

Stephen Baxter

REALITY DUST

AD 5408

An explosion of light: the moment of her birth.

She cried out.

A sense of self flooded through her body. She had arms, legs; her limbs were flailing. She was falling, and glaring light wheeled about her.

... But she remembered another place: a black sky, a world - no, a moon - a face before her, smiling gently. This won’t hurt. Close your eyes.

A name. Callisto.

But the memories were dissipating. ‘No!’

She landed hard, face down, and was suffused by sudden pain. Her face was pressed into dust, rough, gritty particles, each as big as a moon to her staring eyes.

The flitter rose from liberated Earth like a stone thrown from a blue bowl. The little cylindrical craft tumbled slowly as it climbed, sparkling, and Hama Druz marvelled at the beauty of the mist-laden, subtly curved landscape swimming around him, drenched as it was in clear bright sunlight.

The scars of the Occupation were still visible. Away from the great Conurbations, much of the land glistened silver-grey where starbreaker beams and Qax nanoreplicators had chewed up the surface of the Earth, life and rocks and all, turning it into a featureless silicate dust.

‘But already,’ he pointed out eagerly, ‘life’s green is returning. Look, Nomi, there, and there . . .’

His companion, Nomi Ferrer, grunted sceptically. ‘But that greenery has nothing to do with edicts from your Interim Coalition of Governance, or all your philosophies. That’s the worms, Hama, turning Qax dust back into soil. Just the worms, that’s all.’

Hama would not be put off. Nomi, once a ragamuffin, was an officer in the Green Army, the most significant military force yet assembled in the wake of the departing Qax. She was forty years old, her body a solid slab of muscle, with burn marks disfiguring one cheek. And, in Hama’s judgement, she was much too sunk in cynicism.

He slapped her on the shoulder. ‘Quite right. And that’s how we must be, Nomi: like humble worms, content to toil in the darkness, to turn a few scraps of our land back the way they should be. That should be enough for any life.’

Nomi just snorted.

Already the two-seat flitter was beginning its descent, towards a Conurbation. Still known by its Qax registration of 11729, the Conurbation was a broad, glistening sprawl of bubble-dwellings blown from the bedrock, and linked by the green-blue of umbilical canals. Hama saw that many of the dome-shaped buildings had been scarred by fire, some even cracked open. But the blue-green tetrahedral sigil of free Earth had been daubed on every surface.

A shadow passed over the Conurbation’s glistening rooftops. Hama shielded his eyes and squinted upwards. A fleshy cloud briefly eclipsed the sun. It was a Spline ship: a living starship kilometres across, its hardened epidermis pocked with monitor and weapon emplacements. He suppressed a shudder. For generations the Spline had been the symbol of Qax dominance. But now the Qax had gone, and this abandoned Spline was in the hands of human engineers, who sought to comprehend its strange biological workings.

On the outskirts of the Conurbation there was a broad pit scooped out of the ground, its crudely scraped walls denoting its origin as post-Occupation: human, not Qax. In this pit rested a number of silvery, insectile forms, and as the flitter fell further through the sunlit air, Hama could see people moving around the gleaming shapes, talking, working. The pit was a shipyard, operated by and for humans, who were slowly rediscovering yet another lost art; for no human engineer had built a spacecraft on Earth for three hundred years.

Hama pressed his face to the window - like a child, he knew, reinforcing Nomi’s preconception of him - but to Lethe with self-consciousness. ‘One of those ships is going to take us to Callisto. Imagine it, Nomi - a moon of Jupiter!’

But Nomi scowled. ‘Just remember why we’re going there: to hunt out jasofts - criminals and collaborators. It will be a grim business, Hama, no matter how pretty the scenery.’

The flitter slid easily through the final phases of its descent, and the domes of the Conurbation loomed around them.

There was a voice, talking fast, almost babbling.

‘There is no time. There is no space. We live in a universe of static shapes. Do you see? Imagine a grain of dust that represents all the particles in our universe, frozen in time. Imagine a stupendous number of such dust grains, representing all the possible shapes the particles can take. This is reality dust, a dust of the Nows. And each grain is an instant, in a possible history of the universe.’ A snapping of fingers. ‘There. There. There. Each moment, each juggling of the particles, a new grain. The reality dust contains all the arrangements of matter there could ever be. Reality dust is an image of eternity . . .’

She lay there, face pressed into the dirt, wishing none of this was happening.

Hands grabbed her, by shoulder and hip. She was dragged, flipped over on her back. The sky above was dazzling bright.

A face loomed, silhouetted. She saw a hairless scalp, no eyebrows or lashes. The face itself was rounded, smoothed over, as if unformed. But she had a strong impression of great age.

‘This won’t hurt,’ she whispered, terrified. ‘Close your eyes.’

The face loomed closer. ‘Nothing here is real.’ The voice was harsh, without inflection. A man? ‘Not even the dust.’

‘Reality dust,’ she murmured.

‘Yes. Yes! It is reality dust. If you live, remember that.’

The face receded, turning away.

She tried to sit up. She pressed her hands into the loose dust, crushing low, crumbling structures, like the tunnels of worms. She glimpsed a flat horizon, a black, oily sea, forest-covered hills. She was on a beach of silvery, dusty sand. The sky was a glowing dome. The air was full of mist; she couldn’t see far in any direction, as if she were trapped in a glowing bubble.

Her companion was mid-sized, his body shapeless and sexless. He was dressed in a coverall of a nondescript colour. He cast no shadow in the bright diffuse light.

She glanced down at herself. She was wearing a similar coverall. She fingered its smooth fabric, baffled.

The man was walking slowly, limping, as though exhausted. Walking away, leaving her alone.

‘Please,’ she said.

Without stopping, he called back, ‘If you stay there you’ll die.’

‘What’s your name?’

‘Pharaoh. That is all the name I have left, at any rate.’

She thought hard. Those sharp birth memories had fled, but still . . . ‘Callisto, My name is Callisto.’

Pharaoh laughed. ‘Of course it is.’

Without warning, pain swamped her right hand. She snatched it to her chest. The skin felt as if it had been drenched in acid.

The sea had risen, she saw, and the black, lapping fluid had covered her hand. Where the fluid had touched, the flesh was flaking away, turning to chaotic dust, exposing sketchy bones that crumbled and fell in thin slivers.

She screamed. She had only been here a moment, and already such a terrible thing had happened.

Pharaoh limped back to her. ‘Think beyond the pain.’

‘I can’t—’

‘Think. There is no pain.’

And, as he said it, she realised it was true. Her hand was gone, her arm terminating in a smooth, rounded stump. But it didn’t hurt. How could that be?

‘What do you feel?’

‘Diminished,’ she said.

‘Good,’ he said. ‘You’re learning. There is no pain here. Only forgetting.’

The black, sticky fluid was lapping near her legs. She scrambled away. But when she tried to use her missing right hand she stumbled, falling flat.

Pharaoh locked his hand under her arm and hauled her to her feet. The brief exertion seemed to exhaust him; his face smoothed further, as if blurring. ‘Go,’ he said.

‘Where?’

‘Away from the sea.’ And he pushed her, feebly, away from the ocean.

She looked that way doubtfully. The beach sloped upward sharply; it would be a difficult climb. Above the beach there was what looked like a forest, tall shapes like trees, a carpet of something like grass. She saw people moving in the darkness between the trees. But the forest was dense, a place of colourless, flat shadows, made grey by the mist.

She looked back. Pharaoh was standing where she had left him, a pale, smoothed-over figure just a few paces from the lapping, encroaching sea, already dimmed by the thick white mist.

She called, ‘Aren’t you coming?’

‘Go.’

‘I’m afraid.’

‘Asgard. Help her.’

Callisto turned.

There was a woman, not far away, crawling over the beach. She seemed to be plucking stray grass blades from the dust, cramming them into her mouth. Her face was a mask of wrinkles, complex, textured - a stark contrast to Pharaoh’s smoothed-over countenance. Querulous, the woman snapped, ‘Why should I?’

‘Because I once helped you.’

The woman got to her feet, growling.

Callisto quailed from her. But Asgard took her good hand and began to haul her up the beach.

Callisto looked back once more. The oil-black sea lapped thickly over a flat, empty beach. Pharaoh had gone.

As they made their way to Hama’s assigned office, Nomi drew closer to Hama’s side, keeping her weapons obvious.

The narrow corridors of Conurbation 11729 were grievously damaged by fire and weaponry - scars inflicted not by Qax, but by humans. In some places there was even a smell of burning.

And the corridors were crowded: not just with former inhabitants of the Qax-built city, but with others Hama couldn’t help but think of as outsiders.

There were ragamuffins - like Nomi herself - the product of generations who had waited out the Occupation in the ruins of ancient human cities, and other corners of wilderness Earth. And there were returned refugees, the descendants of people who had fled to the outer moons and even beyond Sol system to escape the Qax’s powerful, if inefficient, grasp. Some of these returned space travellers were exotic indeed, with skin darkened by the light of other stars, and frames made spindly or squat by other gravities - even eyes replaced by Eyes, mechanical supplements. And most of them had hair: hair sprouting wildly from their heads and even their faces, in colours of varying degrees of outrage. They made the Conurbation’s Occupation-era inhabitants, with their drab robes and shaven heads, look like characterless drones.

The various factions eyed each other with suspicion, even hostility; Hama saw no signs of unity among liberated mankind.

Hama’s office turned out to be a spacious room, the walls lined with data slates. It even had a natural-light window, overlooking a swathe of the Conurbation and the lands beyond. This prestigious room had once, of course, been assigned to a jasoft - a human collaborator administering Earth on behalf of the Qax - and Hama felt a deep reluctance to enter it.

For Hama, up to now, the liberation had been painless, a time of opportunity and freedom, like a wonderful game. But that, he knew, was about to change. Hama Druz, twenty-five years old, had been assigned to the Commission for Historical Truth, the tribunal appointed to investigate and try collaboration crimes. His job was to hunt out jasofts.

Some of these collaborators were said to be pharaohs, kept alive by Qax technology, perhaps for centuries . . . Some, it was said, were even survivors of the pre-Occupation period, when human science had advanced enough to beat back death. If the jasofts were hated, the pharaohs had been despised most of all; for the longer they had lived, the more loyalty they owed to the Qax, and the more effectively they administered the Qax regime. And that regime had become especially brutal after a flawed human rebellion more than a century earlier.

Hama, accompanied by Nomi, would spend a few days here, acquainting himself with the issues around the collaborators. But to complete his assignment he would have to travel far beyond the Earth: to Jupiter’s moon, Callisto, in fact. There - according to records kept during the Occupation by the jasofts themselves - a number of pharaohs had fled to a science station maintained by one of their number, a man named Reth Cana.

For the next few days Hama worked through the data slates assembled for him, and received visitors, petitions, claimants. He quickly learned that there were many issues here beyond the crimes of the collaborator class.

The Conurbation itself faced endless problems day to day. The Conurbations had been deliberately designed by the Qax as temporary cities. It was all part of the grand strategy of the latter Occupation; the Qax’s human subjects were not allowed ties of family, of home, of loyalty to anybody or anything - except perhaps the Occupation itself. A Conurbation wasn’t a home; sooner or later you would be moved on.

The practical result was that the hastily constructed Conurbation was quickly running down. Hama read gloomily through report after report of silting-up canals and failing heating or lighting and crumbling dwelling places. People were sickening of diseases long thought vanished from the planet - even hunger had returned.

And then there were the wars.

The aftermath of the Qax’s withdrawal - the overnight removal of the government of Earth after three centuries - had been extremely turbulent. In less than a month humans had begun fighting humans once more. It had taken a chaotic half-year before the Coalition had coalesced, and even now, around the planet, brushfire battles still raged against warlords armed with Qax weaponry.

It had been the jasofts, of course, who had been the focus of the worst conflicts. In many places jasofts, including pharaohs, had been summarily executed. Elsewhere the jasofts had gone into hiding, or fled off-world, or had even fought back. The Coalition had quelled the bloodshed by promising that the collaborators would be brought to justice before its new Commission for Historical Truth.

But Hama - alone in his office, poring over his data slates - knew that justice was easier promised than delivered. How were short-lived humans - dismissively called mayflies by the pharaohs - to try crimes that might date back centuries? There were no witnesses save the pharaohs themselves; no formal records save those maintained under the Occupation; no testimony save a handful of legends preserved through the endless dissolutions of the Conurbations; not even any physical evidence since the Qax’s great Extirpation had wiped the Earth clean of its past.

What made it even more difficult, Hama was slowly discovering, was that the jasofts were useful.

It was a matter of compromise, of practical politics. The jasofts knew how the world worked, on the mundane level of keeping people alive, for they had administered the planet for centuries. So some jasofts - offered amnesties for cooperating - were discreetly running parts of Earth’s new, slowly coalescing administration under the Coalition, just as they had under the Qax.

And meanwhile, children were going hungry.

Hama had, subtly, protested against his new assignment. He felt his strength lay in philosophy, in abstraction. He longed to rejoin the debates going on in great constitutional conventions all over the planet, as the human race, newly liberated from the Qax, sought a new way to govern itself.

But his appeal against reassignment had been turned down. There was simply too much to do now, too great a mess to clear up, and too few able and trustworthy people available to do it.

As he witnessed the clamour of the crowds around the failing food dispensers, Hama felt a deep determination that things should be fixed, that such a situation as this should not recur. And yet, to his shame, he looked forward to escaping from all this complexity to the cool open spaces of the Jovian system.

It was while he was in this uncertain mood that the pharaoh sought him out.

Asgard led her to the fringe of the forest. There, ignoring Callisto, she hunkered down and began to pull at strands of grass, ripping them from the ground and pushing them into her mouth.

Callisto watched doubtfully. ‘What should I do?’

Asgard shrugged. ‘Eat.’

Reluctantly Callisto got to her knees. Favouring her truncated arm, it was difficult to keep her balance. With her left hand she pulled a few blades of the grass stuff from the dust. She crammed the grass into her mouth and chewed. It was moist, tasteless, slippery. She found that the grass blades weren’t connected to roots. Rather they seemed to blend back into the dust, to the tube-like structures there.

People moved through the shadows of the forest, digging at the roots with their bare hands, pushing fragments of food into their faces.

‘My name,’ she said, ‘is Callisto.’

Asgard grunted. ‘Your dream-name.’

‘I remembered it.’

‘No, you dreamed.’

‘What is this place?’

‘It isn’t a place.’

‘What’s it called?’

‘It has no name.’ Asgard held up a blade of grass. ‘What colour is this?’

‘Green,’ Callisto said immediately. But that wasn’t true. It wasn’t green. What colour, then? She realised she couldn’t say.

Asgard laughed, and shoved the blade in her mouth.

Callisto looked down the beach. ‘What happened to Pharaoh?’

Asgard shrugged. ‘He might be dead by now. Washed away by the sea.’

‘Why doesn’t he come up here, where it’s safe?’

‘Because he’s weak. Weak and mad.’

‘He saved me from the sea.’

‘He helps all the newborns.’

‘Why?’

‘How should I know? But it’s futile. The ocean rises and falls. Every time it comes a little closer, higher up the beach. Soon it will lap right up here, to the forest itself.’

‘We’ll have to go into the forest.’

‘Try that and Night will kill you.’

Night? Callisto looked into the forest’s darkness, and shuddered.

Asgard eyed Callisto with curiosity, no sympathy. ‘You really are a newborn, aren’t you?’ She dug her hand into the dust, shook it until a few grains were left on her palm. ‘You know what the first thing Pharaoh said to me was? “Nothing is real.” ‘

‘Yes—’

‘ “Not even the dust. Because every grain is a whole world.” ‘ She looked up at Callisto, calculating.

Callisto gazed at the sparkling grains, wondering, baffled, frightened. Too much strangeness.

I want to go home, she thought desperately. But where, and what, is home?

Two women walked into Hama’s office: one short, squat, her face a hard mask, and the other apparently younger, taller, willowy. They both wore bland, rather scuffed Occupation-era robes - as he did - and their heads were shaven bare.

The older woman met his gaze steadily. ‘My name is Gemo Cana. This is my daughter. She is called Sarfi.’

Hama eyed them with brief curiosity. The daughter, Sarfi, averted her eyes. She looked very young, and her face was thin, her skin sallow.

This was a routine appointment. Gemo Cana was, supposedly, a representative of a citizens’ group concerned about details of the testimony being heard by the preliminary hearings of the Truth Commission. The archaic words of family - daughter, mother - were still strange to Hama, but they were becoming increasingly more common, as the era of the Qax cadres faded from memory.

He welcomed them with his standard opening remarks. ‘My name is Hama Druz. I am an adviser to the Interim Coalition and specifically to the Commission for Historical Truth. I will listen to whatever you wish to tell me and will help you any way I can; but you must understand that my role here is not formal, and—’

‘You’re tired,’ Gemo Cana said.

‘What?’

She stepped forward and studied him, her gaze direct, disconcerting. ‘It’s harder than you thought, isn’t it? Running an office, a city - a world. Especially as you must work by persuasion, consent.’ She walked around the room, ran a finger over the data slates fixed on the walls, and paused before the window, gazing out at the glistening rooftops of the Conurbation, the muddy blue-green of the canals. Hama could see the Spline ship rolling in the sky, a wrinkled moon. She said, ‘It was difficult enough in the era of the Qax, whose authority, backed by Spline gunships, was unquestionable.’

‘And,’ asked Hama, ‘how exactly do you know that?’

‘This used to be one of my offices.’

Hama reached immediately for his desktop.

‘Please.’ The girl, Sarfi, reached out towards him, then seemed to think better of it. ‘Don’t call your guards. Hear us out.’

He stood. ‘You’re a jasoft. Aren’t you, Gemo Cana?’

‘Oh, worse than that,’ Gemo murmured. ‘I’m a pharaoh . . . You know, I have missed this view. The Qax knew what they were doing when they gave us jasofts the sunlight.’

She was the first pharaoh Hama had encountered face to face. Before her easy authority, her sense of dusty age, Hama felt young, foolish, his precious philosophies half-formed. And he found himself staring at the girl; he hadn’t even known pharaohs could have children.

Deliberately he looked away, seeking a way to regain control of the situation. ‘You’ve been in hiding.’

Gemo inclined her head. ‘I spent a long time working in offices like this one, Hama Druz. Longer than you can imagine. I always knew the day would come when the Qax would leave us exposed, us pharaohs.’

‘So you prepared.’

‘Wouldn’t you? I was doing my duty. I didn’t want to die for it.’

‘Your duty to Qax occupiers?’

‘No,’ she said, a note of weariness in her voice. ‘You seem more intelligent than the rest; I had hoped you might understand that much. It was a duty to mankind, of course. It always was.’

He tapped a data slate on his desk. ‘Gemo Cana. I should have recognised the name. You are one of the most hunted jasofts. Your testimony before the Commission—’

She snapped, ‘I’m not here to surrender, Hama Druz, but to ask for your help.’

‘I don’t understand.’

‘I know about your mission to Callisto. To the enclave there. Reth has been running a science station since before the Occupation. Now you are going out there to close him down.’

He said grimly, ‘These last few years have not been a time for science.’

She nodded. ‘So you believe science is a luxury, a plaything for easier times. But science is a thread in the tapestry of our humanity - a thread Reth has maintained. Do you even know what he is doing out there?’

‘Something to do with life forms in the ice—’

‘Oh, much more than that. Reth has been exploring the nature of reality - seeking a way to abolish time itself.’ She smiled coolly. ‘I don’t expect you to understand. But it has been a fitting goal, in an era when the Qax have sought to obliterate human history - to abolish the passage of time from human consciousness . . .’

He frowned. Abolishing time? Such notions were strange to him, meaningless. He said, ‘We have evidence that the science performed on Callisto was only a cover - that many pharaohs fled there during the chaotic period following the Qax withdrawal.’

‘Only a handful. There only ever was a handful of us, you know. And now that some have achieved a more fundamental escape, into death, there are fewer than ever.’

‘What do you want?’

‘I want you to take us there.’

‘To Callisto?’

‘We will remain in your custody, you and your guards. You may restrain us as you like. We will not try anything - heroic. All we want is sanctuary. They will kill us, you see.’

‘The Commission is not a mob.’

She ignored that. ‘I am not concerned for myself, but for my daughter. Sarfi has nothing to do with this; she is no jasoft.’

‘Then she will not be harmed.’

Gemo just laughed.

‘You are evading justice, Gemo Cana.’

She leaned forward, resting her hands on the desk nonchalantly; this really had once been her office, he realised. ‘There is no justice here,’ she hissed. ‘How can there be? I am asking you to spare my daughter’s life. Later, I will gladly return to face whatever inquisition you choose to set up.’

‘Why would this Reth help you?’

‘His name is Reth Cana,’ she said. ‘He is my brother. Do you understand? Not my cadre sibling. My brother.’

Gemo Cana; Reth Cana; Sarfi Cana. In the Qax world, families had been a thing for ragamuffins and refugees, and human names had become arbitrary labels; the coincidence of names had meant nothing to Hama. But to these ancient survivors, a shared name was a badge of kinship. He glanced at Gemo and Sarfi, uneasy in the presence of these close primitive ties, of mother and brother and daughter.

Abruptly the door opened. Nomi Ferrer walked in, reading from a data slate. ‘Hama, your ship is ready to go. But I think we have to—’ She looked up, and took in the scene at a glance. In an instant she was at Gemo’s side, with a laser pistol pressed against the pharaoh’s throat. ‘Gemo Cana,’ she hissed. ‘How did you get in here?’

Sarfi stepped towards Nomi, hands fluttering like birds.

Hama held up his hand. ‘Nomi, wait.’

Nomi was angered. ‘Wait for what? Standing orders, Hama. This is a Category One jasoft who hasn’t presented herself to the Commission. I should already have killed her.’

Gemo smiled thinly. ‘It isn’t so easy, is it, Hama Druz? You can theorise all you want about justice and retribution. But here, in this office, you must confront the reality of a mother and her child.’

Sarfi said to Hama, ‘If your guard kills my mother, she kills me too.’

‘No,’ said Hama. ‘We aren’t barbarians. You have nothing to fear—’

Sarfi reached out and swept her arm down at the desk - no, Hama saw, startled; her arm passed through the desk, briefly breaking up into a cloud of pixels, boxes of glowing colour.

‘You’re a Virtual,’ he whispered.

‘Yes. And do you want to know where I live?’ She stepped up to her mother and pushed her hand into Gemo’s skull.

Gemo observed his lack of comprehension. ‘You don’t know much about us, do you, even though you presume to judge us? Hama, pharaohs rarely breed true.’

‘Your daughter was mortal?’

‘The Qax’s gift was ambiguous. We watched our children grow old and die. That was our reward for serving the Qax; perhaps your Commission will accept that historical truth. And when she died—’

‘When she died, you downloaded her into your head?’

‘Nowhere else was safe,’ Gemo said. ‘And I was glad to, um, make room for her. I have lived a long time; there were memories I was happy to shed.’

Nomi said harshly, ‘But she isn’t your daughter. She’s a copy.’

Gemo closed her eyes. ‘But she’s all I have left.’

Hama felt moved, and repelled, by this act of obsessive love.

Sarfi looked away, as if ashamed.

There was a low concussion. The floor shuddered. Hama could hear running footsteps, cries.

Nomi Ferrer understood immediately. ‘Lethe. That was an explosion.’

The light dropped, as if some immense shadow were passing over the sky. Hama ran to the window.

All around the Conurbation, ships were lifting, hauled into the sky by silent technology, an eerie rising. But they entered a sky that was already crowded, darkened by the rolling, meaty bulk of a Spline craft, from whose flanks fire spat.

Hama cringed from the brute physical reality of the erupting conflict. And he knew who to blame. ‘It’s the jasofts,’ he said. ‘The ones taken to orbit to help with the salvaging of the Spline. They took it over. And now they’ve come here, to rescue their colleagues.’

Gemo Cana smiled, squinting up at the sky. ‘Sadly, stupidity is not the sole prerogative of mayflies. This counter-coup cannot succeed. And then, when this Spline no longer darkens the sky, your vengeance will not be moderated by show trials and bleats about justice and truth. You must save us, Hama Druz. Now!’

Sarfi pressed her hands to her face.

Hama stared at Gemo. ‘You knew. You knew this was about to happen. You timed your visit to force me to act.’

‘It’s all very complicated, Hama Druz,’ Gemo said softly, manipulating. ‘Don’t you think so? Get us out of here - all of us - and sort it out later.’

Nomi pulled back the pharaoh’s head. ‘You know what I think? I think you’re a monster, pharaoh. I think you killed your daughter, long ago, and stuck her in your head. An insurance against a day like today.’

Gemo, her face twisted by Nomi’s strong fingers, forced a smile. ‘Even if that were true, what difference would it make?’ And she gazed at Hama, waiting for his decision.

Obeying Nomi’s stern voice commands, the ship rose sharply. Hama felt no sense of acceleration as shadows slipped over his lap.

This small craft was little more than a translucent hemisphere. In fact it would serve as a lifedome, part of a greater structure waiting in Earth orbit to propel him across Sol system. The three of them, plus Sarfi, were jammed into a cabin made for two. The Virtual girl was forced to share the space already occupied by Hama and Gemo. Where her projection intersected their bodies it dimmed and broke up, and she averted her face; Hama was embarrassed by this brutal indignity.

The ship emerged from its pit and rushed directly beneath the looming belly of the attacking Spline; Hama had a brief, ugly glimpse of fleeing, crumpled flesh, oozing scars metres long, glistening weapon emplacements like stab wounds.

The ship reached clear sky. The air was crowded. Ships of all sizes cruised above Conurbation 11729, seeking to engage the rogue Spline. Hama saw, with a sinking heart, that one of the ancient, half-salvaged ships had already crashed back to Earth. It had made a broad crater, a wound in the ground circled by burning blown-silicate buildings. Already people had died today, irreplaceable lives lost for ever.

The ship soared upward. Earth quickly folded over into a glowing blue abstraction, pointlessly beautiful, hiding the gruesome scenes on its surface; the air thinned, the sky dimming through violet, to black. The ship began to seek out the orbiting angular structure that would carry it to the outer planets.

Hama began to relax, for the first time since Gemo had revealed herself. Despite everything that had happened he was relieved to leave behind the complications of the Conurbation; perhaps in the thin light of Jupiter the dilemmas he would have to face would be simpler.

Gemo Cana said carefully, ‘Hama Druz, tell me something. Now that we all know who and what we are—’

‘Yes?’

‘In your searching, has your inquisition turned up a pharaoh called Luru Parz?’

‘She’s on the list but I don’t believe she’s been found,’ Hama said. ‘Why? Did you know her?’

‘In a way. You could say I created her, in fact. She was always the best of us, I thought, the best and brightest, once she had clarified her conscience. I thought of her as a daughter.’

The Virtual copy of her real daughter, Sarfi, turned away, expressionless.

Nomi cursed.

A vast winged shape sailed over the blue hide of Earth, silent, like a predator.

Hama’s heart sank at the sight of this new, unexpected intruder. What now?

Nomi said softly, ‘Those wings must be hundreds of kilometres across.’

‘Ah,’ said Gemo. ‘Just like the old stories. The ship is like a sycamore seed . . . But none of you remembers sycamore trees, do you? Perhaps you need us, and our memories, after all.’

Nomi said, anger erupting, ‘People are dying down there because of your kind, Gemo—’

Hama placed a hand on Nomi’s arm. ‘Tell us, pharaoh. Is it Qax?’

‘Not Qax,’ she said. ‘Xeelee.’ It was the first time Hama had heard the name. ‘That is a Xeelee nightfighter,’ said Gemo. ‘The question is - what does it want here?’

There was a soft warning chime.

The ship shot away from Earth. The planet dwindled, becoming a sparking blue bauble over which a black-winged insect crawled.

Callisto joined the community of foragers.

Dwelling where the forest met the beach, the people ate the grass, and sometimes leaves from the lower branches, even loose flaps of bark. The people were wary, solitary. She didn’t learn their names - if they had any - nor gained a clear impression of their faces, their sexes. She wasn’t even sure how many of them there were here. Not many, she thought.

Callisto found herself eating incessantly. With every mouthful she took she felt herself grow, subtly, in some invisible direction - the opposite to the diminution she had suffered when she lost her hand to the burning power of the sea. There was nothing to drink - no fluid save the oily black ink of the ocean, and she wasn’t tempted to try that. But it didn’t seem to matter.

Callisto was not without curiosity. She explored, fitfully.

The beach curved away, in either direction. Perhaps this was an island, poking out of the looming black ocean. There was no bedrock, not as far as she could dig. Only the drifting, uniform dust.

Tiring of Asgard’s cold company, she plucked up her courage and walked away from the beach, towards the forest.

There were structures in the dust: crude tubes and trails, like the markings of worms or crabs. The grass emerged, somehow, coalescing from looser dust formations. The grass grew sparsely on the open beach, but at the fringe of the forest it gathered in dense clumps.

Deeper inside the forest’s gathering darkness the grass grew longer yet, plaiting itself into ropy vine-like plants. And deeper still she saw things like trees looming tall, plaited in turn out of the vines. Thus the trees weren’t really ‘trees’ but tangles of ropy vines. And everything was connected to everything else.

She pushed deeper into the forest. Away from the lapping of the sea and the wordless rustle of the foraging people at the forest fringe, it grew dark, quiet. Grass ropes wrapped around her legs, tugging, yielding with reluctance as she passed. This was a drab, still, lifeless place, she thought. In a forest like this there ought to be texture: movement, noise, scent. So, anyhow, her flawed memories dimly protested.

She came to a particularly immense tree. It was a tangle of grassy ropes, melding above her head into a more substantial whole that rose above the surrounding vegetative mass and into the light of the sky. But a low mist lay heavily, obscuring her view of the tree’s upper branches.

She felt curiosity spark. What could she see if she climbed above the mist?

She placed her hand on the knotted-up lower trunk, then one foot, and then the other. The stuff of the tree was hard and cold.

At first the climbing was easy, the components of the ‘trunk’ loosely separated. She found a way to lodge her bad arm in gaps in the trunk so she could release her left hand briefly, and grab for a new handhold before she fell back. But as she climbed higher the ropy sub-trunks grew ever more tangled.

High above her the trunk soared upwards, daunting, disappearing into the mist. When she looked down, she saw how the ‘roots’ of this great structure dispersed over the forest floor, branching into narrower trees and vine-thin creepers and at last clumps of grass, melting into the underlying dust. She felt unexpectedly exhilarated by this small adventure—

There was a snarl, of greed and anger. It came from just above her head. She quailed, slipped. She finished up dangling by her one hand.

She looked up.

It was human. Or, it might once have been human. It must have been four, five times her size. It was naked, and it clung to the tree above her, upside down, so that a broad face leered, predator’s eyes fixed on her. Its limbs were cylinders of muscle, its chest and bulging belly massive, weighty. And it was male: an erection poked crudely between its legs. She hadn’t been able to see it for the mist, until she had almost climbed into it.

It thrust its mouth at her, hissing. She could smell blood on its breath.

She screamed and lost her grip.

She fell, sliding down the trunk. She scrabbled for purchase with her feet and her one good hand. She slammed repeatedly against the trunk, and when she hit the ground the wind was knocked out of her.

Above her, the beast receded, still staring into her eyes.

Ignoring the aches of battered body and torn feet, she blundered away, running until she reached the openness of the beach. For an unmeasured time she lay there, drawing comfort from the graininess of the dust.

The craft was called a GUTship.

As finally assembled, it looked something like a parasol of iron and ice. The canopy of the parasol was the surface ferry, now serving as a habitable lifedome, and the ‘handle’ was the GUTdrive unit itself, embedded in a block of asteroid ice which served as reaction mass. The shaft of the parasol, separating the lifedome from the drive unit, was a kilometre-long spine of metal bristling with antennae and sensors.

In a hundred subtle ways the ship showed its age. Every surface in the lifedome was scuffed and polished from use, the soft coverings of chairs and bunks were extensively patched, and many of the major systems bore the scars of rebuilding. The design was centuries old. The ship itself had been built long before the Occupation, and lovingly maintained by a colony of refugees who had seen out the Qax era huddled in the asteroid belt.

GUT, it seemed, was an acronym for Grand Unified Theory. Once, Gemo whispered, unified-theory energy had fuelled the expansion of the universe. In the heart of each GUT engine asteroid ice was compressed to conditions resembling the initial singularity - the Big Bang. There, the fundamental forces governing the structure of matter merged into a single unified superforce. When the matter was allowed to expand again, the phase energy of the decomposing superforce, released like heat from condensing steam, was used to expel asteroid matter as a vapour rocket.

Remarkable, exotic, strange. This might be a primitive ship compared to a mighty Spline vessel, but Hama had never dreamed that mere humans had once mastered such technologies.

But when they were underway, with the lifedome opaqued over and all the strangeness shut out, none of that mattered. To Hama it was like being back in the Conurbations, in the enclosed, claustrophobic days before the Occupation was lifted. A deep part of his mind seemed to believe that what lay beyond these walls - occupied Earth, or endless universe - did not matter, so long as he was safe and warm. He felt comfortable in his mobile prison, and was guilty to feel that way.

All that changed when they reached Callisto.

The sun was shrunk to the tiniest of discs by Jupiter’s remoteness, five times as far as Earth from the central light. When Hama held up his hand it cast sharp, straight shadows, the shadows of infinity, and he felt no warmth.

And through this rectilinear, reduced light, Callisto swam.

They entered a wide, slow orbit around the ice moon. The satellite was like a dark, misty twin of Earth’s Moon. Its surface was crowded with craters - even more so than the Moon’s, for there were none of the giant lava-flood seas that smoothed over much lunar terrain. The largest craters were complex structures, plains of pale ice surrounded by multiple arcs of folded and cracked land, like ripples frozen into shattered ice and rock. Some of these features were the size of continents, large enough to stretch around this lonely moon’s curved horizon, evidently the results of immense, terrifying impacts.

But these great geological sculptures were oddly smoothed out, the cracks and ripples reduced to shallow ridges. Unlike Earth’s rocky Moon, Callisto was made of rock and water ice. Over billions of years the ice had suffered viscous relaxation; it flowed and slumped. The most ancient craters had simply subsided, like geological sighs, leaving these spectacular palimpsests.

‘The largest impact structure is called Valhalla,’ Gemo was saying. ‘Once there were human settlements all along the northern faces of the circular ridges. All dark now, of course - save where Reth has made his base.’

Nomi grunted, uninterested in tourism. ‘Then that’s where we land.’

Hama gazed out. ‘Remarkable,’ he said. ‘I never imagined—’

Gemo said caustically, ‘You are a drone of the Occupation. You never imagined a universe beyond the walls of your Conurbation, you never even saw the sunlight, you have never lived. You have no memory. And yet you presume to judge. Do you even know why Callisto is so-called? It is an ancient myth. Callisto was a nymph, beloved of Zeus and hated by jealous Hera, who metamorphosed her into a bear . . .’ She seemed to sense Hama’s bafflement. ‘Ah, but you don’t even remember the Gree-chs, do you?’

Nomi confronted her. ‘You administered the Extirpation, pharaoh. Your arrogance over the memories you took from us is—’

‘Ill-mannered,’ Hama said smoothly, and he touched Nomi’s shoulder, seeking to calm the situation. ‘A lack of grace that invalidates her assumption of superiority over us. Don’t concern yourself, Nomi. She condemns herself and her kind every time she speaks.’

Gemo glared at him, full of contempt.

But now Jupiter rose.

The four of them crowded to see. They bobbed in the air like balloons, thrust into weightlessness now the drive was shut down.

The largest of planets was a dish of muddy light, of cloudy bands, pink and purple and brown. Where the bands met, Hama could see fine lines of turbulence, swoops and swirls like a lunatic water-colour. But a single vast storm disfigured those smooth bands, twisting and stirring them right across the southern hemisphere of the planet, as if the whole of Jupiter were being sucked into some central maw.

As perhaps it was. There was a legend that, a century before, human rebels called the Friends of Wigner had climaxed their revolt by escaping back through time, across thousands of years, and had hurled a black hole into the heart of Jupiter. The knot of compressed spacetime was already distorting Jupiter’s immense, dreamy structure, and perhaps in time would destroy the great world altogether. It was a fantastic story, probably no more than a tale spun for comfort during the darkest hours of Occupation. Still, it was clear that something was wrong with Jupiter. Nobody knew the truth - except perhaps the pharaohs, and they would say nothing.

Hama saw how Sarfi, entranced, tried to rest her hand against the lifedome’s smooth transparency. But her hand sank into the surface, crumbling, and she snatched it away quickly. Such incidents seemed to cause Sarfi deep distress - as if she had been programmed with deep taboos about violating the physical laws governing ‘real’ humans. Perhaps it even hurt her when such breaches occurred.

Gemo Cana did not appear to notice her daughter’s pain.

The lifedome neatly detached itself from the ship’s drive section and swept smoothly down from orbit. Hama watched the moon’s folded-over, crater-starred landscape flatten out, the great circular ramparts of Valhalla marching over the close horizon.

The lifedome settled to the ice with the gentlest of crunches. A walkway extended from a darkened building block and nuzzled hesitantly against the ship. A hatch sighed open.

Hama stood in the hatchway. The walkway was a transparent, shimmering tube before him, concealing little of the silver-black morphology of the collapsed landscape beyond. The main feature was the big Valhalla ridge, of course. Seen this close it was merely a rise in the land, a scarp that marched to either horizon: it would have been impossible to tell from the ground that this was in fact part of a circular rampart surrounding a continent-sized impact scar, and Hama felt insignificant, dwarfed.

He forced himself to take the first step along the walkway.

To walk through Callisto’s crystal stillness was enchanting; he floated between footsteps in great bounds. The gravity here was about an eighth of Earth’s, comparable to the Moon’s.

Gemo mocked his pleasure. ‘You are like Armm-stron and Alldinn on the Moon.’

Nomi growled, ‘More Gree-chs, pharaoh?’

Reth Cana was waiting to meet them at the end of the walkway. He was short, squat, with a scalp of crisp white hair, and he wore a practical-looking coverall of some papery fabric. He was scowling at them, his face a round wrinkled mask. Beyond him, Hama glimpsed extensive chambers, dug into the ice, dimly lit by a handful of floating globe lamps - extensive, but deserted.

Hama’s gaze was drawn back to Reth. He looks like Gemo.

Gemo stepped forward now, and she and Reth faced each other, brother and sister separated for centuries. They were like copies of each other, subtly morphed. Stiffly, they embraced. Sarfi hung back, watching, hands folded before her.

Hama felt excluded, almost envious of this piece of complex humanity. How must it be to be bound to another person by such strong ties - for life?

Reth stepped away from his sister and inspected Sarfi. Without warning he swept his clenched fist through the girl’s belly. He made a trail of disrupted pixels, like a fleshy comet. Sarfi crumpled over, crying out. The sudden brutality shocked Hama.

Reth laughed. ‘A Virtual? I didn’t suspect you were so sentimental, Gemo.’

Gemo stepped forward, her mouth working. ‘But I remember your cruelty.’

Now Reth faced Hama. ‘And this is the one sent by Earth’s new junta of children.’

Hama shrank before Reth’s arrogance and authority. His accent was exotic - antique, perhaps; there was a rustle of history about this man. Hama tried to keep his voice steady. ‘I have a specific assignment here, sir—’

Reth snorted. ‘My work, a project of centuries, deals with the essence of reality itself. It is an achievement of which you have no understanding. If you had a glimmer of sensitivity you would leave now. Just as, if you and your mayfly friends had any true notion of duty, you would abandon your petty attempts at governing and leave it to us.’

Nomi growled, ‘You think we got rid of the Qax just to hand over our lives to the likes of you?’

Reth glared at her. ‘And can you really believe that we would have administered the withdrawal of the Qax with more death and destruction than you have inflicted?’

Hama stood straight. ‘I’m not here to discuss hypotheticals with you, Reth Cana. We are pragmatic. If your work is in the interest of the species—’

Reth laughed out loud; Hama saw how his teeth were discoloured, greenish. ‘The interest of the species.’ He stalked about the echoing cavern, posturing. ‘Gemo, I give you the future. If this young man has his way, science will be no more than a weapon! . . . And if I refuse to cooperate with his pragmatism?’

Nomi said smoothly, ‘Those who follow us will be a lot tougher. Believe it, jasoft.’

Gemo listened, stony-faced. ‘They mean it, Reth.’

‘Tomorrow,’ Reth said to Hama. ‘Twelve hours from now. I will demonstrate my work, my results. But I will not justify it to the likes of you; make of it what you will.’ And he swept away into shadows beyond the fitful glow of the hovering globe lamps.

Nomi said quietly to Hama, ‘Reth is a man who has spent too long alone.’

‘We can deal with him,’ Hama said, with more confidence than he felt.

‘Perhaps. But why is he alone? Hama, we know that at least a dozen pharaohs came to this settlement before the Occupation was ended, and probably more during the collapse. Where are they?’

Hama frowned. ‘Find out.’

Nomi nodded briskly.

The oily sea lapped even closer now. The beach was reduced to a thin strip, trapped between forest and sea.

Callisto walked far along the beach. There was nothing different, just the same dense forest, the oily sea. Here and there the sea had already covered the beach, encroaching into the forest, and she had to push into the vegetation to make further progress. Everywhere she found the tangle of roots and vine-like growths. Where the rising liquid had touched, the grasses and vines and trees crumbled and died, leaving bare, scattered dust.

The beach curved around on itself.

So she was on an island. At least she had learned that much. Eventually, she supposed, that dark sea would rise so high it would cover everything. And they would all die.

There was no night. When she was tired, she rested on the beach, eyes closed.

There was no time here - not in the way she seemed to remember, on some deep level of herself: no days, no nights, no change. There was only the beach, the forest, that black oily sea, lapping ever closer, all of it under a shadowless grey-white sky.

She looked inward, seeking herself. She found only fragments of memory: an ice moon, a black sky - a face, a girl’s perhaps, delicate, troubled, but the face broke up into blocks of light. She didn’t like to think about the face. It made her feel lonely. Guilty.

She asked Asgard about time.

Asgard, gnawing absently on a handful of bark chips, ran a casual finger through the reality dust, from grain to grain. ‘There,’ she said. ‘Time passing. From one moment to the next.

For we, you see, are above time.’

‘I don’t understand.’

‘Of course you don’t. A row of dust grains is a shard of story. A blade of grass is a narrative. Where the grass knits itself into vines and trees, that story deepens. And if I eat a grass blade I absorb its tiny story, and it becomes mine. So Pharaoh said. And I don’t know who told him. Do you see?’

‘No,’ said Callisto frankly.

Asgard just looked at her, apathetic, contemptuous.

There was a thin cry, from the ocean. Callisto, shading her eyes, looked that way.

It had been a newborn, thrust arbitrarily into the air, just as Callisto had been. But this newborn had fallen, not to the comparative safety of the dust, but direct into the sea. She - or he - made barely a ripple on that placid black surface. Callisto saw a hand raised briefly above the sluggish meniscus, the flesh already dissolving, white bones curling. And then it was gone, the newborn lost.

Callisto felt a deep horror. It might have happened to her.

Now, as she looked along the beach, she saw dark masses - a mound of flesh, the grisly articulation of fingers - fragments of the suddenly dead, washed up on this desolate beach. This had happened before, she realised. Over and over.

She said, ‘We can’t stay here.’

‘No,’ Asgard agreed reluctantly. ‘No, we can’t.’

Hama, with Reth and Gemo, rode a platform of metal deep into the rocky heart of Callisto.

The walls of the pressurised shaft, sliding slowly upwards, were lined with slick transparent sheets, barring them from the ice. Hama reached out with a fingertip. The wall surface was cold and slippery, lubricated by a thin sheet of condensation from the chill air. There were no signs of structure, of strata in the ice; here and there small bores had been dug away from the shaft, perhaps as samples.

Callisto was a ball of dirty water ice. Save for surface impacts, nothing had happened to this moon since it accreted from the greater cloud that had formed the Jupiter system. The inner moons - Io, Europa, Ganymede - were heated, to one degree or another, by tidal pumping from Jupiter. So Europa, under a crust of ice, had a liquid ocean; and Io was driven by that perennial squeezing to spectacular volcanism. But Callisto had been born too far from her huge parent for any of that gravitational succour. Here, the only heat was a relic of primordial radioactivity; here there had been no geology, no volcanism, no hidden ocean.

Nevertheless, it seemed, Reth Cana had found life here. And, as the platform descended, Reth’s cold excitement seemed to mount.

Nomi Ferrer was pursuing her own researches, in the settlement and out on the surface. But she had insisted that Hama be escorted by a squat, heavily armed drone robot. Both Reth and Gemo ignored this silent companion, as if it were somehow impolite of Hama to have brought it along.

Nor did either of them mention Sarfi, who hadn’t accompanied them. To Hama it did not seem human to disregard one’s daughter, Virtual or otherwise. But then, what was ‘human’ about a near-immortal traitor to the race? What was human about Reth, this man who had buried himself alone in the ice of Callisto, obsessively pursuing his obscure project, for decade after decade?

Even though the platform was small and cramped, Hama felt cold and alone; he suppressed a shiver.

The platform slowed, creaking, to a halt. He faced a chamber dug into the ice.

Reth said, ‘You are a kilometre beneath the surface. Go ahead. Take a look.’

Hama saw that the seal between the lip of the circular platform and the roughly cut ice was not perfect. He felt a renewed dread at his reliance on ancient, patched-up technology. But, suppressing hesitation, he stepped off the platform and into the ice chamber. With a whirr of aged bearings, the drone robot followed him.

Hama stood in a rough cube perhaps twice his height. It had been cut out of the ice, its walls lined by some clear glassy substance; it was illuminated by two hovering light globes. On the floor there was a knot of instrumentation, none of it familiar to Hama, along with a heap of data slates, some emergency equipment, and scattered packets of food and water. This was a working place, impersonal.

Reth stepped past him briskly. ‘Never mind the gadgetry; you wouldn’t understand it anyhow. Look.’ And he snapped his fingers, summoning one of the floating globes. It came to hover at Hama’s shoulder.

Hama leaned close to inspect the cut-away ice of the wall. He could see texture: the ice was a pale, dirty grey, polluted by what looked like fine dust grains - and, here and there, it was stained by colour, crimson and purple and brown.

Reth had become animated. ‘I’d let you touch it,’ he breathed. ‘But the sheeting is there to protect it from us - not the other way around. The biota in there is much more ancient, unevolved, fragile than we are; the bugs on your breath might wipe it out in an instant. The prebiotic chemicals were probably delivered here by comet impacts during Callisto’s formation. There is carbon and hydrogen and nitrogen and oxygen. The biochemistry is a matter of carbon-carbon chains and water - like Earth’s, but not precisely so. Nothing exactly like our DNA structures . . .’

‘Spell it out,’ Gemo said casually, prowling around the gadgetry. ‘Remember, Reth, the education of these young is woefully inadequate.’

‘This is life,’ Hama said. ‘Native to Callisto.’

‘Life - yes,’ Reth said. ‘The highest forms are about equivalent to Earth’s bacteria. But - native? I believe the life forms here have a common ancestor with Earth life, buried deep in time - and that they are related to the more extravagant biota of Europa’s buried ocean, and probably most of the living things found elsewhere in Sol system. Do you know the notion of panspermia? Life, you see, may have originated in one place, perhaps even outside the system, and then was spread through the worlds by the spraying of meteorite-impact debris. And everywhere it landed, life embarked on a different evolutionary path.’

‘But here,’ Hama said slowly, fumbling to grasp these unfamiliar concepts, ‘it was unable to rise higher than the level of a bacterium?’

‘There is no room,’ said Reth. ‘There is liquid water here: just traces of it, soaked into the pores between the grains of rock and ice, kept from freezing by the radiogenic heat. But energy flows thin, and replication is very slow - spanning thousands of years.’ He shrugged. ‘Nevertheless there is a complete ecosystem. Do you understand? My Callisto bacteria are rather like the cryptoendoliths found in some inhospitable parts of Earth. In Antarctica, for instance, you can crack open a rock and see layers of green life, leaching nutrients from the stone itself, sheltering from the wind and the desolating cold: communities of algae, cyanobacteria, fungi, yeasts—’

‘Not any more,’ Gemo murmured, running a finger over control panels. ‘Reth, the Extirpation was very thorough, an effective extinction event; I doubt if any of your cryptoendoliths can still survive.’

‘Ah,’ said Reth. ‘A shame.’

Hama straightened up, frowning. He had come far from the cramped caverns of the Conurbations; he was confronting life from another world, half a billion kilometres from Earth. He ought to feel wonder. But these pale shadows evoked only a kind of pity. Perhaps this thin, cold, purposeless existence was a suitable object for the obsessive study of a lonely, half-mad immortal.

Reth’s eyes were on him, hard.

Hama said carefully, ‘We know that before the Occupation, Sol system was extensively explored, by Michael Poole and those who followed him. The records of those times are lost - or hidden,’ he said with a glance at the impassive Gemo. ‘But we do know that everywhere humans went, they found life. Life is commonplace. And in most places we reached, life has attained a much higher peak than this. Why not just catalogue these scrapings and abandon the station?’

Reth threw up his arms theatrically. ‘I am wasting my time. Gemo, how can this mayfly mind possibly grasp the subtleties here?’

She said dryly, ‘I think it would serve you to try to explain, brother.’ She was studying a gadget that looked like a handgun mounted on a floating platform. ‘This, for example.’

When Hama approached this device, his weapon-laden drone whirred warningly. ‘What is it?’

Reth stalked forward. ‘It is an experimental mechanism based on laser light, which . . . It is a device for exploring the energy levels of an extended quantum structure.’ He began to talk rapidly, lacing his language with phrases like ‘spectral lines’ and ‘electrostatic potential wells’, none of which Hama understood.

At length Gemo interpreted for Hama.

‘Imagine a very simple physical system - a hydrogen atom, for instance. I can raise its energy by bombarding it with laser light. But the atom is a quantum system; it can only assume energy levels at a series of specific steps. There are simple mathematical rules to describe the steps. This is called a “potential well”.’

As he endured this lecture, irritation slowly built in Hama; it was clear there was much knowledge to be reclaimed from these patronising, arrogant pharaohs.

‘The potential well of a hydrogen atom is simple,’ said Reth rapidly. ‘The simplest quantum system of all. It follows an inverse-square rule. But I have found the potential wells of much more complex structures.’

‘Ah,’ said Gemo. ‘Structures embedded in the Callisto bacteria.’

‘Yes.’ Reth’s eyes gleamed. He snatched a data slate from a pile at his feet. Lines of numbers chattered over the slate, meaning little to Hama, a series of graphs that sloped sharply before dwindling to flatness: a portrait of the mysterious ‘potential wells’, perhaps.

Gemo seemed to understand immediately. ‘Let me.’ She took the slate, tapped its surface and quickly reconfigured the display. ‘Now, look, Hama: the energies of the photons that are absorbed by the well are proportional to this series of numbers.’

1. 2. 3. 5. 7. 11. 13 . . .

‘Prime numbers,’ Hama said.

‘Exactly,’ snapped Reth. ‘Do you see?’

Gemo put down the slate and walked to the ice wall; she ran her hand over the translucent cover, as if longing to touch the mystery that was embedded there. ‘So inside each of these bacteria,’ she said, ‘there is a quantum potential well that encodes prime numbers.’

‘And much more,’ said Reth. ‘The primes were just the key, the first hint of a continent of structure I have barely begun to explore.’ He paced back and forth, restless, animated. ‘Life is never content simply to subsist, to cling on. Life seeks room to spread. That is another commonplace, young man. But here, on Callisto, there was no room: not in the physical world; the energy and nutrients were simply too sparse for that. And so—’

‘Yes?’

‘And so they grew sideways,’ he said. ‘And they reached orthogonal realms we never imagined existed.’

Hama stared at the thin purple scrapings and chattering primes, here at the bottom of a pit with these two immortals, and feared he had descended into madness.

... 41. 43. 47. 53. 59 . . .

In a suit no more substantial than a thin layer of cloth, Nomi Ferrer walked over Callisto’s raw surface, seeking evidence of crimes.

The sun was low on the horizon, evoking highlights from the curved ice plain all around her. From here, Jupiter was forever invisible, but Nomi saw two small discs, inner moons, following their endless dance of gravitational clockwork.

Gemo Cana had told her mayfly companions how the Jovian system had once been. She told them of Io’s mineral mines, nestling in the shadow of the huge volcano Babbar Patera. She told them of Ganymede: larger than Mercury, heavily cratered and geologically rich - the most stable and heavily populated of all the Jovian moons. And Europa’s icy crust had sheltered an ocean hosting life, an ecosystem much more complex and rewarding than anybody had dreamed. ‘They were worlds. Human worlds, in the end. All gone now, shut down by the Qax. But I remember . . .’

Away from the sun’s glare, lesser stars glittered, surrounding Nomi with immensity. But it was a crowded sky, despite that immensity. Crowded and dangerous. For - she had been warned by the Coalition - the Xeelee craft that had glowered over Earth was now coming here, hotly pursued by a Spline ship retrieved from the hands of jasoft rebels and manned by Green Army officers. What would happen when that miniature armada got here, Nomi couldn’t imagine.

Nomi knew about the Xeelee from barracks-room scuttlebutt. She had tried to educate a sceptical Hama. The Xeelee were a danger mankind encountered long before anybody had heard of the Qax; in the Occupation years they had become legends of a deep-buried, partly extirpated past - and perhaps they were monsters of the human future. The Xeelee were said to be godlike entities so aloof that humans might never understand their goals. Some scraps of Xeelee technology, like starbreaker beams, had fallen into the hands of ‘lesser’ species, like the Qax, and transformed their fortunes. The Xeelee seemed to care little for this - but, on occasion, they intervened. To devastating effect.

Some believed that by such interventions the Xeelee were maintaining their monopoly on power, controlling an empire which, perhaps, held sway across the Galaxy. Others said that, like the vengeful gods of humanity’s childhood, the Xeelee were protecting the ‘junior races’ from themselves.

Either way, Nomi thought, it’s insulting. Claustrophobic. She felt an unexpected stab of resentment. We only just got rid of the Qax, she thought. And now, this.

Gemo Cana had argued that in such a dangerous universe, humanity needed the pharaohs. ‘Everything humans know about the Xeelee today, every bit of intelligence we have, was preserved by the pharaohs. I refuse to plead with you for my life. But I am concerned that you should understand. We pharaohs were not dynastic tyrants. We fought, in our way, to survive the Qax Occupation, and the Extirpation. For we are the wisdom and continuity of the race. Destroy us and you complete the work of the Qax for them, finish the Extirpation. Destroy us and you destroy your own past - which we preserved for you, at great cost to ourselves.’

Perhaps, Nomi thought. But in the end it was the bravery and ingenuity of one human - a mayfly - that had brought down the Qax, not the supine compromising of the jasofts and pharaohs.

She looked up towards the sun, towards invisible Earth. I just want a sky clear of alien ships, she thought. And to achieve that, perhaps we will have to sacrifice much.

Reth Cana began to describe where the Callisto bugs had ‘gone’, seeking room to grow.

‘There is no time,’ he whispered. ‘There is no space. This is the resolution of an ancient debate - do we live in a universe of perpetual change, or a universe where neither time nor motion exist? Now we understand. Now we know we live in a universe of static shapes. Nothing exists but the particles that make up the universe - that make up us. Do you see? And we can measure nothing but the separation between those particles.

‘Imagine a universe consisting of a single elementary particle, an electron perhaps. Then there could be no space. For space is only the separation between particles. Time is only the measurement of changes in that separation. So there could be no time.

‘Imagine now a universe consisting of two particles . . .’ Gemo nodded. ‘Now you can have separation, and time.’ Reth bent and, with one finger, scattered a line of dark dust grains across the floor. ‘Let each dust grain represent a distance - a configuration of my miniature two-particle cosmos. Each grain is labelled with a single number: the separation between the two particles.’ He stabbed his finger into the line, picking out grains. ‘Here the particles are a metre apart; here a micron; here a light year. There is one special grain, of course: the one that represents zero separation, the particles overlaid. This diagram of dust shows all that is important about the underlying universe - the separation between its two components. And every possible configuration is shown at once, from this god-like perspective.’

He let his finger wander back and forth along the line, tracing out a twisting path in the grains. ‘And here is a history: the two particles close and separate, close and separate. If they were conscious, the particles would think they were embedded in time, that they are coming near and far. But we can see that their universe is no more than dust grains, the lined-up configurations jostling against each other. It feels like time, inside. But from outside, it is just - sequence, a scattering of instants, of reality dust.’

Gemo said, ‘Yes. “It is utterly beyond our power to measure the changes of things by time. Quite the contrary, time is an abstraction at which we arrive by means of the changes of things.” ‘ She eyed Hama. ‘An ancient philosopher. Mach, or Mar-que . . .’

‘If the universe has three particles,’ said Reth, ‘you need three numbers. Three relative distances - the separation of the particles, one from the other - determine the cosmos’s shape. And so the dust grains, mapping possible configurations, would fill up three-dimensional space - though there is still that unique grain, representing the special instant where all the particles are joined. And with four particles—’

‘There would be six separation distances,’ Hama said. ‘And you would need a six-dimensional space to map the possible configurations.’

Reth glared at him, eyes hard. ‘You are beginning to understand. Now. Imagine a space of stupendously many dimensions. ‘ He held up a dust grain. ‘Each grain represents one configuration of all the particles in our universe, frozen in time. This is reality dust, a dust of the Nows. And the dust fills configuration space, the realm of instants. Some of the dust grains may represent slices of our own history.’ He snapped his fingers, once, twice, three times. ‘There. There. There. Each moment, each juggling of the particles, a new grain, a new coordinate on the map. There is one unique grain that represents the coalescing of all the universe’s particles into a single point. There are many more grains representing chaos - darkness - a random, structureless shuffling of the atoms.

‘Configuration space contains all the arrangements of matter there could ever be. It is an image of eternity.’ He waved a fingertip through the air. ‘But if I trace out a path from point to point—’

‘You are tracing out a history,’ said Hama. ‘A sequence of configurations, the universe evolving from point to point.’

‘Yes. But we know that time is an illusion. In configuration space, all the moments that comprise our history exist simultaneously. And all the other configurations that are logically possible also exist, whether they lie along the track of that history or not.’

Hama frowned. ‘And the Callisto bugs—’

Reth smiled. ‘I believe that, constrained in this space and time, the Callisto lifeforms have started to explore the wider realms of configuration space. Seeking a place to play. Life will find a way.’

Nomi toiled up the gentle slope of the ridge that loomed above the settlement. This was one of the great ring walls of the Valhalla system, curving away from this place for thousands of kilometres, rising nearly a kilometre above the surrounding plains.

The land around her was silver and black, a midnight sculpture of ridges and craters. There were no mountains here, none at all; any created by primordial geology or the impacts since Callisto’s birth had long since subsided, slumping into formlessness. There was a thin smearing of black dust over the dirty white of the underlying ice; the dust was loose and fine-grained, and she disturbed it as she passed, leaving bright footprints.

‘. . . Do you understand what you’re looking at?’

The sudden voice startled her; she looked up.

It was Sarfi. She was dressed, as Nomi was, in a translucent protective suit, another nod to the laws of consistency that seemed to bind her Virtual existence. But she left no footprints, nor even cast a shadow.

Sarfi kicked at the black dust, not disturbing a single grain. ‘The ice sublimes - did you know that? It shrivels away, a metre every ten million years - but it leaves the dust behind. That’s why the human settlements were established on the north side of the Valhalla ridges. There it is just a shade colder, and some of the sublimed ice condenses out. So there is a layer of purer ice, right at the surface. The humans lived off ten-million-year frost . . . You’re surprised I know so much. Nomi Ferrer, I was dead before you were born. Now I’m a ghost imprisoned in my mother’s head. But I’m conscious. And I am still curious.’

Nothing in Nomi’s life had prepared her for this conversation. ‘Do you love your mother, Sarfi?’

Sarfi glared at her. ‘She preserved me. She gave up part of herself for me. It was a great sacrifice.’

Nomi thought, You resent her. You resent this cloying, possessive love. And all this resentment bubbles inside you, seeking release. ‘There was nothing else she could have done for you.’

‘But I died anyway. I’m not me. I’m a download. I don’t exist for me, but for her. I’m a walking, talking construct of her guilt.’ She stalked away, climbing the slumped ice ridge.

Gemo started to argue detail with her brother. How was it possible for isolated bacteria-like creatures to form any kind of sophisticated sensorium? - but Reth believed there were slow pathways of chemical and electrical communication, etched into the ice and rock, tracks for great slow thoughts that pulsed through the substance of Callisto. Very well, but what of quantum mechanics? The universe was not made up of neat little particles, but was a mesh of quantum probability waves. - Ah, but Reth imagined quantum probability lying like a mist over his reality dust, constrained by two things: the geometry of configuration space, as acoustic echoes are determined by the geometry of a room; and something called a ‘static universal wave function’, a mist of probability that governed the likelihood of a given Now sharing configuration space with a given other . . .

Hama closed his eyes, his mind whirling. Blocky pixels flickered across his vision, within his closed eyes.

Startled, he looked up. Sarfi was kneeling before him; she had brushed her Virtual fingertips through his skull, his eyes. He hadn’t even known she had come here.

‘I know it’s hard to accept,’ she said. ‘My mother spent a long time making me understand. You just have to open your mind.’

‘I am no fool,’ he said sharply. ‘I can imagine a map of all the logical possibilities of a universe. But it would be just that - a map, a theoretical construct, a thing of data and logic. It would not be a place. The universe doesn’t feel like that, I feel time passing. I don’t experience disconnected instants, Reth’s dusty reality.’

‘Of course not,’ said Reth. ‘But you must understand that everything we know of the past is a record embedded in the present - the fossils and geology of Earth, so cruelly obliterated by the Qax, even the traces of chemicals and electricity in your own brain that comprise your memory, maintaining your illusion of past times. Sarfi herself is an illustration of the point. Gemo, may I—?’

Gemo nodded, unsmiling. Hama noted he hadn’t asked Sarfi’s permission for whatever he was about to do.

Reth tapped a data slate. Sarfi froze, becoming a static, inanimate sculpture of light. Then, after perhaps ten seconds, she melted, began to move once more.

She saw Hama staring at her. ‘What’s wrong?’

Reth, ignoring her, said, ‘The child contains a record of her own shallow past, embedded in her programmes and data stores. She is unaware of intervals of time when she is frozen, or deactivated. If I could start and stop you, Hama Druz, you would wake protesting that your memories contained no gaps. But your memories themselves would have been frozen. I could even chop up your life and rearrange its instants in any way I chose; at each instant you would have an intact set of memories, a record of a past, and you would believe yourself to have lived through a continuous, consistent reality.

‘And thus the maximal-reality dust grains contain embedded within themselves a record of the eras which “preceded” them. Each grain contains brains, like yours and mine, with “memories” embedded in them, frozen like sculptures. And history emerges in configuration space because those rich grains are then drawn, by a least-energy matching principle, to the grains which “precede” and “follow” them . . . You see?’

Sarfi looked to Gemo. ‘Mother? What does he mean?’

Gemo watched her clinically. ‘Sarfi has been reset many times, of course,’ she said absently. ‘I had no wish to see her grow old, accreted with worthless memory. It was rather like the Extirpation, actually. The Qax sought to reset humanity, to abolish the memory of the race. In the ultimate realisation, we would have become a race of children, waking every day to a fresh world, every day a new creation. It was cruel, of course, but theoretically intriguing. Don’t you think?’

Sarfi was trembling.

Now Reth began telling Gemo, rapidly and with enthusiasm, of his plans to explore his continent of configurations. ‘No human mind could apprehend that multi-dimensional domain unaided, of course. But it can be modelled, with metaphors - rivers, seas, mountains. It is possible to explore it . . .’

Hama said, ‘But, if your meta-universe is static, timeless, how could it be experienced? For experience depends on duration.’

Reth shook his head impatiently. He tapped his data slate and beckoned to Sarfi. ‘Here, child.’

Hesitantly, she stepped forward. Now she trailed a worm-like tube of light, as if her image had been captured at each moment in some invisible emulsion. She emerged, blinking, from the tube, and looked back at it, bewildered.

‘Stop these games,’ Hama said tightly.

‘You see?’ Reth said. ‘Here is an evolution of Sarfi’s structure, but mapped in space, not time. But it makes no difference to Sarfi. Her memory at each frozen instant contains a record of her walking across the floor towards me - doesn’t it, dear? And thus, in static configuration space, sentient creatures could have experiences, afforded them by the evolution of information structures across space.’

Hama turned to Sarfi. ‘Are you all right?’

She snapped back, ‘What do you think?’

‘I think Reth may be insane,’ he said.

She stiffened, pulling back. ‘Don’t ask me. I’m not even a mayfly, remember?’

‘It is comforting to know that configuration space exists, Hama,’ Gemo said. ‘Nothing matters, you see: not even death, not even the Extirpation. For we persist, each moment exists for ever, in a greater universe . . .’

It was a philosophy of decadence, Hama thought angrily. A philosophy of morbid contemplation, a consolation for ageless pharaohs as they sought to justify the way they administered the suffering of their fellow creatures. No wonder it appealed to them so much.

Gemo and Reth talked on, more and more rapidly, entering realms of speculation he couldn’t begin to follow.

Callisto told Asgard what she was intending to do. She wanted to climb that tall, braided tree. But she would have to take on Night to do it.

She walked along the narrowing beach, seeking scraps of people, of newborns and others, washed up by the pitiless black sea. She picked up what looked like a human foot. It was oddly dry, cold, the flesh and even the bones crumbling at her touch.

She collected as many of these hideous shards as she could hold, and toiled back along the barren dust.

Then she worked her way through the forest back to the great tree, where she had encountered the creature called Night. She paused every few paces and pushed a section of corpse into the ground. She covered each fragment with ripped-up grass and bits of bark.

‘You’re crazy,’ Asgard said, trailing her, arms full of dried, crumbling flesh and bone.

‘I know,’ Callisto said. ‘I’m going anyway.’

Asgard would not come far enough to reach the tree itself. So Callisto completed her journey alone.

Once more she reached the base of Night’s tree. Once more, her heart thumping hard, she began to climb.

The creature, Night, seemed to have expected her. He moved from branch to branch, far above, a massive blur, and he clambered with ferocious purpose down the trunk.

When she was sure he had seen her she scrambled hurriedly back to the ground.

He followed her - but not all the way to the ground. He clung to his trunk, his broad face broken by that immense, bloody mouth, hissing at her.

She glowered back, and took a tentative step towards the tree. ‘Come get me,’ she muttered. ‘What are you waiting for?’ She took a piece of corpse (a hand - briefly her stomach turned), and she hurled it up at him.

He ducked aside, startled. But as the severed hand came by he caught it neatly in his scoop of a mouth, crunched once and swallowed it whole. He looked down at her with new interest.

And he took one tentative step towards the ground.

‘That’s it,’ she crooned. ‘Come on. Come eat the flesh. Come eat me, if that’s what you want—’

Without warning he leapt from the trunk, immense hands splayed.

She screamed and staggered back. He crashed to the ground perhaps an arm’s length from her. One massive fist slammed into her ankle, sending a stab of pain that made her cry out. If he’d landed on top of her he would surely have crushed her.

The beast, winded, was already clambering to his feet.

She got up and ran, ignoring the pain of her ankle. Night followed her, his lumbering four-legged pursuit slow but relentless. As she ran she kicked open her buried caches of body parts. He snapped them up and gobbled them down, barely slowing. The morsels seemed pathetically inadequate in the face of Night’s giant reality.

She burst out onto the open beach, still running for her life. She reached the lip of the sea, skidding to a halt before the lapping black liquid. Her plan had been to reach the sea, to lure Night into it.

But when she turned, she saw that Night had hesitated on the fringe of the forest, blinking in the light. Perhaps he was aware that she had deliberately drawn him here. He seemed to dismiss her calculations. He stepped forward deliberately, his immense feet sinking into the soft dust. There was no need for him to rush.

Callisto was already exhausted, and, trapped before the sea, there was nowhere for her to run.

Now he was out in the open she saw how far from the human form he had become, with his body a distorted slab of muscle, a mouth that had widened until it stretched around his head. And yet scraps of clothing clung to him, the remnants of a coverall of the same unidentifiable colour as her own. Once this creature, too, had been a newborn here, landing screaming on this desolate beach.

He walked up to her. He towered over her, and she wondered how many unfortunates he had devoured to reach such proportions.

Beyond his looming shoulder, she could see Asgard, pacing back and forth along the beach.

‘Great plan,’ Asgard called. ‘Now what?’

‘I—’

Night raised himself up on his hind legs, huge hands pawing at the air over her head. He roared wordlessly, and bloody breath gushed over her.

Close your eyes, Callisto thought. This won’t hurt.

‘No,’ Asgard said. She took a step towards the looming beast, began to run. ‘No, no, no!’ With a final yell she hurled herself at his back.

He looked around, startled, and swiped at Asgard with one giant paw. She was flung away like a scrap of bark, to land in a heap on the dust. But Night, off-balance, was stumbling backward, back toward the sea.

When his foot sank into the oily ocean, he looked down, as if surprised. Even as he lifted his leg from the fluid the flesh was drying, crumbling, the muscles and bone sloughing away in layers of purple and white. He roared his defiance, and cuffed at the sea - then gazed in horror at one immense hand left shredded by contact with the entropic ooze.

He began to fall, slowly, ponderously. Without a splash, the fluid opened up to accept his immense bulk. He was immediately submerged, the shallow fluid flowing eagerly over him. In one last burst of defiance he broke the surface, mouth open, his flesh dissolving. His face was restored, briefly, to the human, his eyes a startling blue. He cried out, his voice thin: ‘Reth Cana! You betrayed me! ‘

The name sent a shiver of recognition through Callisto.

Then he fell back, and was gone.

She hurried to Asgard. Her chest was crushed, Callisto saw immediately, and her limbs were splayed at impossible angles. Her face was growing smooth, featureless, like a child’s, beautiful in its innocence. Her gaze slid over Callisto.

Callisto cradled Asgard’s head. ‘This won’t hurt,’ she murmured. ‘Close your eyes.’

Asgard sighed, and was still.

‘Let me tell you the truth about pharaohs,’ Nomi said bitterly.

Hama listened in silence. They stood on the Valhalla ridge, overlooking the old, dark settlement; the brightest point on the silver-black surface of Callisto was their own lifedome.

Nomi said, ‘This was just after the Qax left. I got this from a couple of our people who survived, who were there. They found a nest of the pharaohs, in one of the biggest Conurbations - one of the first to be constructed, one of the oldest. The pharaohs retreated into a pit, under the surface dwellings. They fought hard; we didn’t know why. They had to be torched out. A lot of good people, good mayflies, died that day. When our people had dealt with the pharaohs, shut down the mines and drone robots and booby-traps . . . after all that, they went into the pit. It was dark. But it was warm, the air was moist, and there was movement everywhere. Small movements. And, so they say, there was a smell. Of milk.’

Nomi was silent for a long moment; Hama waited.

‘Hama, I can’t have children. I grew up knowing that. So maybe I ought to find some pity for the pharaohs. They don’t breed true - like Gemo and Sarfi. Oh, sometimes their children are born with Qax immortality. But—’

‘Yes?’

‘But they don’t all grow. They stop developing, at the age of two years or one year or six months or a month; some of them even stop growing before they are ready to be born, and have to be plucked from their mothers’ wombs.

‘And that was what our soldiers found in the pit, Hama. Racked up like specimens in a lab, hundreds of them. Must have been accumulating for centuries. Plugged into machines, mewling and crying.’

‘Lethe.’ Maybe Gemo is right, Hama thought; maybe the pharaohs really have paid a price we can’t begin to understand.

‘The pit was torched . . .’

Hama thought he saw a shadow pass across the sky, the scattered stars. ‘Why are you telling me this, Nomi?’

‘To show you that pharaohs have experiences we can’t share. And they do things we would find incomprehensible. To figure them out you have to think like a pharaoh.’

‘You’ve found something, haven’t you?’

Nomi pointed. ‘There’s a line of shallow graves over there. Not hard to find, in the end.’

‘Ah.’

‘The killings seemed to be uniform, the same method every time. A laser to the head. The bodies seemed peaceful,’ Nomi mused. ‘Almost as if they welcomed it.’

He had killed them. Reth had killed the other pharaohs who came here, one by one. But why? And why would an immortal welcome death? Only if - Hama’s mind raced - only if she were promised a better place to go, a safer place—

Everything happened at once.

A shadow, unmistakable now, spread out over the stars: a hole in the sky, black as night, winged, purposeful. And, low towards the horizon, there was a flare of light.

‘Lethe,’ said Nomi softly. ‘That was the GUTship. It’s gone - just like that.’

‘Then we aren’t going home.’ Hama felt numb; he seemed beyond shock.

‘. . . Help me. Oh, help me . . .’

A form coalesced before them, a cloud of blocky pixels. Hama made out a sketch of limbs, a face, an open, pleading mouth. It was Sarfi, and she wasn’t in a protective suit. Her face was twisted in pain; she must be breaking all her consistency overrides to have projected herself to the surface like this.

Hama held out his gloved hands, driven by an impulse to hold her; but that, of course, was impossible.

‘Please,’ she whispered, her voice a thin, badly realised scratch. ‘It is Reth. He plans to kill Gemo.’

Nomi set off down the ridge slope in a bouncing low-G run.

Hama said to Sarfi, ‘Don’t worry. We’ll help your mother.’

Now he saw anger in that blurred, sketchy face. ‘To Lethe with her! Save me . . .’ The pixels dispersed into a meaningless cloud, and winked out.

Callisto returned to the great tree.

The trunk soared upwards, a pillar of rigid logic and history and consistency. She slapped its hide, its solidity giving her renewed confidence. And now there was no Night, no lurking monster, waiting up there to oppose her.

Ignoring the aches of her healing flesh and torn muscles, she began to climb.

As she rose above the trunk’s lower tangle and encountered the merged and melded upper length, the search for crevices became more difficult, just as it had before. But she was immersed in the rhythm of the climb, and however high she rose there seemed to be pocks and ledges moulded into the smooth surface of the trunk, sufficient to support her progress.

Soon she had far surpassed the heights she had reached that first time she had tried. The mist was thick here, and when she looked down the ground was already lost: the great trunk rose from blank emptiness, as if rooted in nothingness.

But she thought she could see shadows, moving along the trunk’s perspective-dwindled immensity: the others from the beach, some of them at least, were following her on her unlikely adventure.

And still she climbed.

The trunk began to split into great arcing branches that pushed through the thick mist. She paused, breathing deeply. Some of the branches were thin, spindly limbs that dwindled away from the main trunk. But others were much more substantial, highways that seemed anchored to the invisible sky.

She picked the most solid-looking of these upper branches, and continued her climb. Impeded by her damaged arm, her progress was slow but steady. It was actually more difficult to make her way along this tipped-over branch than it had been to climb the vertical trunk. But she was able to find handholds, and places where she could she wrap her limbs around the branch.

The mist thickened further until she could see nothing around her but this branch: no sky or ground, not even the rest of this great tree, as if nothing existed but herself and the climb, as if she had been toiling for ever along this branch that came from the mist and finished in the mist.

And then, without warning, she broke through the fog.

In a pit dug into the heart of Callisto, illuminated by a single hovering globe lamp, Gemo Cana lay on a flat, hard pallet, unmoving. Her brother stood hunched over her, working at her face with gleaming equipment. ‘This won’t hurt. Close your eyes . . .’

‘Stop this!’ Sarfi ran forward. She pushed her hands into Gemo’s face, crying out as the pain of consistency violation pulsed through her.

Gemo turned, blindly. Hama saw that a silvery mask had been laid over her face, hugging the flesh. ‘Sarfi . . . ?’

Nomi stepped forward, laser pistol poised. ‘Stop this obscenity.’

Reth wore a mask of his own, a smaller cap that covered half his face; the exposed eye peered at them, hard, suspicious, calculating. ‘Don’t try to stop us. You’ll kill her if you try. Let us go, Hama Druz.’

Nomi raised her pistol at his head.

But Hama touched the soldier’s arm. ‘Not yet.’

On her pallet, Gemo Cana turned her head blindly. She whispered, ‘There’s so much you don’t understand.’

Hama snapped, ‘You’d better make us understand, Reth Cana, before I let Nomi here off the leash.’

Reth paced back and forth. ‘Yes - technically, this is a kind of death. But not a single one of the pharaohs who passed through here did it against his or her will.’

Hama frowned. ‘ “Technically”? “Passed through”?’

Reth stroked the metal clinging to Gemo’s face; his sister turned her head in response. ‘The core technology is an interface to the brain via the optic nerve. In this way I can connect the quantum structures which encode human consciousness to the structures stored in the Callisto bacteria - or, rather, the structures which serve as, um, a gateway to configuration space . . .’

Hama started to see it. ‘You’re attempting to download human minds into your configuration space.’

Reth smiled. ‘It was not enough, you see, to study configuration space at second-hand, through quantum structures embedded in these silent bacteria. The next step had to be direct apprehension by the human sensorium.’

‘The next step in what?’

‘In our evolution, perhaps,’ Reth murmured. ‘With the help of the Qax, we have banished death. Now we can break down the walls of this shadow theatre we call reality.’ He eyed Hama. ‘This dismal pit is not a grave, but a gateway. And I am the gatekeeper.’

Hama said tightly, ‘You destroy minds for the promise of afterlife - a promise concocted of theory and a scraping of cryptoendolith bacteria.’

‘Not a theory,’ Gemo whispered. ‘I have seen it.’

Nomi grunted, ‘We don’t have time for this.’

But Hama asked, despite himself: ‘What was it like?’

It was, Gemo said, a vast, spreading landscape, under a towering sky; she had glimpsed a beach, a rising, oily sea, an immense mountain shrouded in mist . . .

Reth stalked back and forth, arms spread wide. ‘We remain human, Hama Druz. I cannot apprehend a multi-dimensional continuum. So I sought a metaphor. A human interface. A beach of reality dust. A sea of entropy, chaos. The structures folded into the living things, the shape of the landscape, represent consistency - what we time-bound creatures apprehend as causality.’

‘And the rising sea?’

‘The cosmos-spanning threat of the Xeelee,’ he said, smiling thinly. ‘And the grander rise of entropy, across the universe, which will bring about the obliteration of all possibility.

‘Configuration space is real, Hama Druz. This isn’t a new idea; Pleh-toh saw that, thousands of years ago . . . Ah, but you know nothing of Pleh-toh, do you? The higher manifold always existed, you see, long before the coming of mankind, of life itself. All that has changed is that through the patient, blind growth of the Callisto bacteria, I have found a way to reach it. And there we can truly live for ever—’

The ice floor shuddered, causing them to stagger.

Reth peered up the length of the shaft, smiling grimly. ‘Ah. Our visitors make their presence known. Callisto is a small, hard, static world; it rings like a bell even at the fall of a footstep. And the footsteps of the Xeelee are heavy indeed.’

Sarfi pushed forward again, hands twisting, agonised by her inability to touch and be touched. She said to Gemo, ‘Why do you have to die?’

Gemo’s voice was slow, sleepy; Hama wondered what sedative agents Reth had fed her. ‘You won’t feel anything, Sarfi. It will be as if you never existed at all, as if all this pain never occurred. Won’t that be better?’

The ground shuddered again, waves of energy from some remote Xeelee-induced explosion pulsing through Callisto’s patient ice, and the walls groaned, stressed.

Hama tried to imagine the black sea, the sharp-grained dust of the beach. Hama had once visited the ocean - Earth’s ocean - to oversee the reclamation of an abandoned Qax sea farm. He remembered the stink of ozone, the taste of salt in the damp air. He had hated it.

Reth seemed to sense his thoughts. ‘Ah, but I forgot. You are creatures of the Conurbations, of the Extirpation. Of round-walled caverns and a landscape of grey dust. But this is how the Earth used to be, you see, before the Qax unleashed their nanotech plague. No wonder you find the idea strange. But not us.’ He slipped his hand into his sister’s. ‘For us, you see, it will be like coming home.’

On the table, Gemo was convulsing, her mouth open, laced with drool.

Sarfi screamed, a thin wail that echoed from the high walls of the shaft. Once more she reached out to Gemo; once more her fluttering fingers passed through Gemo’s face, sparkling.

‘Gemo Cana is a collaborator,’ Nomi said. ‘Hama, you’re letting her escape justice.’

Yes, Hama thought, surprised. Nomi, in her blunt way, had once more hit on the essence of the situation here. The pharaohs were the refugees now, and Reth’s configuration space - if it existed at all - might prove their ultimate bolt-hole. Gemo Cana was escaping, leaving behind the consequences of her work, for good or ill. But did that justify killing her?

Sarfi was crying. ‘Mother, please. I’ll die.’

The pharaoh turned her head. ‘Hush,’ said Gemo. ‘You can’t die. You were never alive. Don’t you see that?’ Her back arched. ‘Oh . . .’

Sarfi straightened and looked at her hands. The illusion of solidity was breaking down, Hama saw; pixels swarmed like fat, cubic insects, grudgingly cooperating to maintain the girl’s form. Sarfi looked up at Hama, and her voice was a flat, emotionless husk, devoid of intonation and character. ‘Help me.’

Again Hama reached out to her; again he dropped his hands, the most basic of human instincts invalidated. ‘I’m sorry.’

‘It hurts.’ Her face swarmed with pixels that erupted from the crumbling surface of her skin and fled her body, as if evaporating; she was becoming tenuous, unstable.

Hama forced himself to meet her gaze. ‘It’s all right,’ he murmured. ‘It will be over soon . . .’ On and on, meaningless endearments; but she gazed into his eyes, as if seeking refuge there.

For a last instant her face congealed, clearly, from the dispersing cloud. ‘Oh! ‘ She reached out to him with a hand that was no more than a mass of diffuse light. And then, with a silent implosion, her face crumbled, eyes closing.

Gemo shuddered once, and was still.

Hama could feel his heart pulse within him. His humanity was warm in this place of cold and death. Nomi placed her strong hand on his shoulder, and he relished its fierce solidity.

Hama faced Reth. ‘You are monsters.’

Reth smiled easily. ‘Gemo is beyond your mayfly reproach. And as for the Virtual child - you may learn, Hama Druz, if you pass beyond your current limitations, that the first thing to be eroded by time is sentiment.’

Hama flared. ‘I will never be like you, pharaoh. Sarfi was no toy.’

‘But you still don’t see it,’ Reth said evenly. ‘She is alive - but our time-bound language can’t describe it - she persists, somewhere out there, beyond the walls of our petty realisation.’

Again the moon shuddered, and primordial ice groaned.

Reth murmured, ‘Callisto was not designed to take such hammer blows. The situation is reduced, you see. Now there is only me.’

‘And me.’ Nomi raised the laser pistol.

‘Is this what you want?’ Reth asked of Hama. ‘To cut down centuries of endeavour with a bolt of light?’

Hama shook his head. ‘You really believe you can reach your configuration space - that you can survive there?’

‘But I have proof,’ Reth said. ‘You saw it.’

‘All I saw was a woman dying on a slab.’

Reth glowered at him. ‘Hama Druz, make your decision.’

Nomi aimed the pistol. ‘Hama?’

‘Let him go,’ Hama said bitterly. ‘He has only contempt for our mayfly justice anyhow. His death would mean nothing, even to him.’

Reth grinned and stepped back. ‘You may be a mayfly, but you have the beginnings of wisdom, Hama Druz.’

‘Yes,’ Hama said quietly. ‘Yes, I believe I do. Perhaps there is something there, some new realm of logic to be explored. But you, Reth, are blinded by your arrogance and your obsessions. Surely this new reality is nothing like the Earth of your childhood. And it will have little sympathy for your ambitions. Perhaps whatever survives the download will have no resemblance to you. Perhaps you won’t even remember who you were. What then?’

Reth’s mask sparkled; he raised his hand to his face. He made for the pallet, to lie beside the cooling body of his sister. But he stumbled and fell before he got there.

Hama and Nomi watched, neither moving to help him.

Reth, on his hands and knees, turned his masked face to Hama. ‘You can come with me, Hama Druz. To a better place, a higher place.’

‘You go alone, pharaoh.’

Reth forced a laugh. He cried out, his back arching. Then he fell forward, and was still.

Nomi raked the body with laser fire. ‘Good riddance,’ she growled. ‘Now can we get out of here?’

There was a mountain.

It rose high above the night-dark sea, proudly challenging the featureless, glowing sky. Rivers flowed from that single great peak, she saw: black and massive, striping its huge conical flanks, merging into great tumbling cascades that poured into the ocean.

The mountain was the centre of the world, thrusting from the sea.

She was high above an island, a small scrap of land that defied the dissolving drenching of the featureless sea. Islands were few, small, scattered, threatened everywhere by the black, crowding ocean.

But, not far away, there was another island, she saw, pushing above the sea of mist. It was a heaping of dust on which trees grew thickly, their branches tangled. In fact the branches reached across the neck of sea that separated this island from her own. She thought she could see a way to reach that island, scrambling from tree to tree, following a great highway of branches. The other island rose higher than her own above the encroaching sea. There, she thought, she - and whoever followed her - would be safe from lapping dissolution. For now, anyhow.

But what did that mean? What would Pharaoh have said of this - that the new island was an unlikely heap of reality dust, further from looming entropic destruction?

She shook her head. The deeper meaning of her journey scarcely mattered - and nor did its connection to any other place. If this world were a symbol, so be it: this was where she lived, and this was where she would, with determination and perseverance, survive.

She looked one last time at the towering mountain. Damaged arm or not, she itched to climb it, to challenge its negentropic heights. But in the future, perhaps. Not now.

Carefully, clinging to her branch with arms and legs and her one good hand, she made her way along the branch to the low-probability island. One by one, the people of the beach followed her.

In the mist, far below, she glimpsed slow, ponderous movement: huge beasts, perhaps giant depraved cousins of Night. But, though they bellowed up at her, they could not reach her.

Once more Hama and Nomi stood on the silver-black surface of Callisto, under a sky littered with stars. Just as before, the low, slumped ridges of Valhalla marched to the silent horizon.

But this was no longer a world of antiquity and stillness. The shudders were coming every few minutes now. In places the ice crust was collapsing, ancient features subsiding, here and there sending up sprays of dust and ice splinters that sparkled briefly before falling back, all in utter silence.

Hama thought back to a time before this assignment, to the convocations he had joined, the earnest talk of political futures and ethical settlements. He had been a foolish boy, he thought, his ideas half-formed. Now, when he looked into his heart, he saw crystal-hard determination. In an implacably hostile universe humanity must survive, whatever the cost.

‘No more pharaohs,’ Hama murmured. ‘No more immortality. That way lies selfishness and arrogance and compromise and introversion and surrender. A brief life burns brightly - that is the way.’

Nomi growled, ‘Even now you’re theorising, Hama? Let’s count the ways we might die, standing right here. The Xeelee starbreaker might cream us. One of these miniature quakes might erupt right under us. Or maybe we’ll last long enough to suffocate in our own farts, stuck inside these damn suits. What do you think? I don’t know why you let that arrogant pharaoh kill himself.’

Hama murmured, ‘You see death as an escape?’

‘If it’s easy, if it’s under your control - yes.’

‘Reth did escape,’ Hama said. ‘But I don’t think it was into death.’

‘You believed all that stuff about theoretical worlds?’

‘Yes,’ Hama said. ‘Yes, in the end I think I did believe it.’

‘Why?’

‘Because of them.’ He gestured at the sky. ‘The Xeelee. If our second-hand wisdom has any validity at all, we know that the Xeelee react to what they fear. And almost as soon as Reth constructed his interface to his world of logic and data, as soon as the pharaohs began to pass into it, they came here.’

‘You think the Xeelee fear us?’

‘Not us. The bugs in the ice: Reth’s cryptoendoliths, dreaming their billion-year dreams . . . The Xeelee seem intent on keeping those dreams from escaping. And that’s why I think Reth hit on a truth, you see. Because the Xeelee see it too.’

Now, over one horizon, there was a glowing crimson cloud, like dawn approaching - but there could be no dawn on this all-but-airless world.

‘Starbreaker light,’ murmured Nomi. ‘The glow must be vapour, ice splinters, dust, thrown up from the trench they are digging.’

Hama felt a fierce anger burn - anger, and a new certainty. ‘Once again aliens have walked into our system, for their own purposes, and we can do nothing to stop them. This mustn’t happen again, Nomi. You know, perhaps the Qax were right to attempt the Extirpation. If we are to survive in this dangerous universe we must remake ourselves, without sentiment, without nostalgia, without pity. Let this be an end - and a beginning, a new Day Zero. History is irrelevant. Only the future is important.’ He longed to be gone from this place, to bring his hard new ideas to the great debates that were shaping the future of humankind.

‘You’re starting to frighten me, my friend,’ Nomi said gently. ‘But not as much as that.’

Now the Xeelee nightfighter itself came climbing above the shattered fog of the horizon. Somehow in his ardour Hama had forgotten this mortal peril. The nightfighter was like an immense, black-winged bird. Hama could see crimson Starbreaker light stab down again and again into the passive, defenceless ice of Callisto. The shuddering of the ground was constant now, as that mass of shattered ice and steam rolled relentlessly towards them.

Nomi grabbed him; holding each other, they struggled to stay on their feet as ice particles battered their faceplates. A tide of destruction spanned Callisto from horizon to horizon. There was, of course, no escape.

And then the world turned silver, and the stars swam.

Hama cried out, clinging to Nomi, and they fell. They hit the ice hard, despite the low gravity.

Nomi, combat-hardened, was on her feet immediately. An oddly pink light caught her squat outline. But Hama, winded, bewildered, found himself gazing up at the stars.

Different stars? No. Just - moved. The Xeelee ship was gone, vanished.

He struggled to his feet.

The wave of vapour and ice was subsiding, as quickly as it had been created; there was no air here to prevent the parabolic fall of the crystals back to the shattered land, little gravity to prevent the escape of the vapour into Jovian space. The land’s shuddering ceased, though he could feel deep slow echoes of huge convulsions washing through the rigid ground.

But the stars had moved.

He turned, taking in the changed sky. Surely the shrunken sun was a little further up the dome of sky. And a pink slice of Jupiter now showed above the smoothly curved horizon, where none had shown before on this tide-locked moon.

Nomi touched his arm, and pointed deep into the ice. ‘Look.’

It was like some immense fish, embedded in the ground, its spreadeagled black wings clearly visible through layers of dusty ice. A red glow shone fitfully at its heart; as Hama watched it sputtered, died, and the buried ship grew dark.

Nomi said, ‘At first I thought the Xeelee must have lit up some exotic super-drive and got out of here. But I was wrong. That thing must be half a kilometre down. How did it get there?’

‘I don’t think it did,’ Hama said. He turned away and peered at Jupiter. ‘I think Callisto moved, Nomi.’

‘What?’

‘It didn’t have to be far. Just a couple of kilometres. Just enough to swallow up the Xeelee craft.’

Nomi was staring at him. ‘That’s insane. Hama, what can move a moon?’

Why, a child could, Hama thought in awe. A child playing on a beach - if every grain on that beach is a slice in time. I see a line sketched in the dust, a history, smooth and complete. I pick out a grain with Callisto positioned just here. And I replace it with a grain in which Callisto is positioned just a little further over there. As easy, as wilful, as that.

No wonder the Xeelee are afraid.

A new shuddering began, deep and powerful.

‘Lethe,’ said Nomi. ‘What now?’

Hama shouted, ‘Not the Xeelee this time. Callisto spent four billion years settling into its slow waltz around Jupiter. Now I think it’s going to have to learn those lessons over again.’

‘Tides,’ Nomi growled.

‘It might be enough to melt the surface. Perhaps those cryptoendoliths will be wiped out after all, and the route to configuration space blocked. I wonder if the Xeelee planned it that way all along.’

He saw a grin spread across Nomi’s face. ‘We aren’t done yet.’ She pointed.

Hama turned. A new moon was rising over Callisto’s tight horizon. It was a moon of flesh and metal, and it bore a sigil, a blue-green tetrahedron, burned into its hide.

‘The Spline ship, by Lethe,’ Nomi said. She punched Hama’s arm. ‘Our Spline. So the story goes on for us, my friend.’

Hama glared down into the ice, at the Xeelee craft buried there. Yes, the story goes on, he thought. But we have introduced a virus into the software of the universe. And I wonder what eyes will be here to see, when that ship is finally freed from this tortured ice.

An orifice opened up in the Spline’s immense hide. A flitter squirted out and soared over Callisto’s ice, seeking a place to land.

Exhausted, disoriented, Callisto and her followers stumbled down the last length of trunk and collapsed to the ground.

She dug her good hand into the loose grains of reality dust. She felt a surge of pride, of achievement. This island, an island of a new possibility, was her island now.

Hers, perhaps, but not empty, she realised slowly. There was a newborn here: lost, bewildered, suddenly arrived. She saw his face smoothing over, working with anguish and doubt, as he forgot.

But when his gaze lit on her, he became animated.

He tried to stand, to walk towards her. He stumbled, weak and drained, and fell on his face.

Dredging up the last of her own strength, she went to him. She dug her hand under him and turned him on his back - as, once, Pharaoh had done for her.

He opened his mouth. Spittle looped between his lips, and his voice was a harsh rasp. ‘Gemo!’ he gasped.

‘My name is Callisto.’

‘I am your brother! I made you! Help me! Love me!’

Something tugged at her: recognition - and resentment.

She held his head to her chest. ‘This won’t hurt,’ she said. ‘Close your eyes.’ And she held him, until the last of his unwelcome memories had leaked away, and, forgetting who he was, he lay still.

The Coalition, hardened by Hama Druz’s doctrines of constancy and racial destiny, proved persistent, and determined. Cleansing themselves of the past, they continued to try to eradicate the undying, for we collaborators embodied the past. We had to flee, to hide.

But our taint of immortality went deeper than those who persecuted us could know. I, already an elder, found a new role.

RIDING THE ROCK

AD 23,479

I

When Luca arrived in the Library conference room, the meeting between Commissary Dolo and Captain Teel was already underway. They sat in hard-backed armchairs, talking quietly, while trays of drinks hovered at their elbows.

Over their heads Virtual dioramas swept by like dreams, translucent, transient. These were the possible destinies of mankind, assembled from the debris of interstellar war by toiling bureaucrats here in Earth’s Library of Futures, and displayed for the amusement of the Library’s guests. But neither Dolo nor Teel were paying any attention to the spectacle.

Luca waited by the door. He was neither patient nor impatient. He was just a Novice, at twenty years old barely halfway through his formal novitiate into the Commission, and Novices expected to wait.

But he knew who this Captain Teel was. An officer in the Green Navy, she had come from her posting on the Front - the informal name for the great ring of human fortification that surrounded the Core of the Galaxy, where the Xeelee lurked, mankind’s implacable foe. The Navy and the Commission for Historical Truth were also, of course, ancient and unrelenting enemies. There was no way Teel, therefore, would adopt the ascetic dress code of the Commission, even here in its headquarters. But her uniform was a subdued charcoal grey shot through with green flashes, and her hair, if not shaved, was cut short; this fighting officer had shown respect, then, for the hive of bureaucrats she had come to visit.

At last Dolo noticed Luca.

Luca said, ‘You sent for me, Commissary.’

Captain Teel turned her head towards him. She looked tired, but Luca saw how the complex, shifting light of multiple futures softened her expression.

Dolo was watching Luca, the corner of his mouth pulled slightly, as if by a private joke. Dolo had no eyebrows, and his skull was shaved, as was Luca’s. ‘Yes, Novice, I called you. I think I’m going to need an assistant on this project, and Lethe knows you need some field experience.’

‘A project, Commissary?’

‘Sit down, shut up, listen and learn.’ Dolo waved a hand, and a third chair drifted in from a corner of the room.

Luca sat, and absently followed their continuing talk.

From scuttlebutt in the dormitories he already had an idea why Captain Teel had been called here to Earth. In a unit of troopers at some desolate corner of the Front, there had been an outbreak of anti-Doctrinal thinking which, it sounded to Luca’s ill-informed ears, might even be religious in character. If so, of course, it was perilous to the greater efficiency of the Third Expansion. An important issue, then. But not very interesting.

Surreptitiously, as they talked, he studied Teel.

He supposed he had expected some battle-scarred veteran of raids on Xeelee emplacements. But this Navy officer was young, surely about the same age as he was himself, at twenty years. Her face was long, the nose narrow and well-carved, her nostrils flaring slightly; her mouth was relaxed but full. Her skin was unblemished - though it was pale, almost bloodless; he reminded himself that of all the countless worlds now inhabited by mankind, on only a handful could a human walk in the open air without a skinsuit. But that paleness gave her skin a translucent quality. But it was not Teel’s features that drew him - she was scarcely conventionally beautiful - but something more subtle, a quality of stillness about her that seemed to pull him towards her like a gravitational field. She was solid, he thought, as if she was the only real person in this place of buzzing bureaucrats. Even before she spoke to him, he knew that Teel was like no one he had ever met before.

‘Novice.’ The Commissary’s gaze neatly skewered Luca.

To his mortification, Luca felt his face flush like a child’s in a new cadre. Captain Teel was looking a little past him, expressionless. ‘I’m sorry,’ he said.

Dolo brushed that aside. ‘Tell me what you are thinking. The surface of your mind.’

Luca looked at Teel. ‘That, with respect, the Captain is young.’

Dolo nodded, his voice forensic. ‘How could one so young - actually younger than you, Novice - have achieved so much?’

Luca said, ‘ “A brief life burns brightly.” ‘

Teel’s lips parted, and Luca thought she sighed. The ancient slogan hung in the air, trite and embarrassing.

Dolo’s smile was cruel. ‘I have come to a decision. I will visit the site of this Doctrinal infringement. And you, Novice, will come with me.’

‘Commissary - you want me to go to the Core?’ It was all but unheard of for a novice to travel so far.

‘I have no doubt it will help you fulfil your fitful promise, Luca. Make the arrangements.’

Suddenly he was dismissed. Luca stood, bowed to the Commissary and Captain, and turned to leave.

Emotions swirled in Luca: embarrassment, surprise, fear - and a strange, unexpected grain of hope. Of course this was all just some game to the Commissary; Dolo had spotted Luca’s reaction to Teel and had impulsively decided to toy with him. Dolo was hugely arrogant. You could hardly expect to become one of the most powerful members of a bureaucracy that ruled the disc of a Galaxy without learning a little arrogance along the way. But for Luca it was a good opportunity, perhaps an invaluable building block for his future career.

And none of that mattered, he knew in his heart, for whatever the wider context Luca was now going to be in the company of this intriguing young Navy officer for weeks, even months to come, and who could say where that would lead?

At the door he glanced back. Teel and Dolo continued to talk of this uninteresting Doctrinal problem at the Galaxy’s Core; still she didn’t look at him.

They were to climb to orbit in a small flitter, and there join the Navy yacht that had brought Teel to Earth.

Luca had only been off Earth a couple of times during his general education, and then on mere hops out of the atmosphere. As the flitter lifted off the ground its hull was made transparent, so that it was as if the three of them were rising inside a drifting bubble. As the land fell away Luca tried to ignore the hot blood that prickled at his neck, and the deeply embarrassingly primeval clenching of his sphincter.

He tried to draw strength from Teel’s stillness. Her eyes were blue, Luca noticed now. He hadn’t been able to make that out before, in the shifting light of the Library.

As they rose the Conurbation was revealed. It was a glistening sprawl of bubble-dwellings blown from the bedrock. The landscape beyond was flat, a plain of glistening silver-grey devoid of hills, and there were no rivers, only the rectilinear gashes of canals. The only living things to be seen, aside from humans, were birds. It was like this over much of the planet. The alien Qax had begun the transformation of the land during their Occupation of Earth, their starbreaker beams and nanoreplicators turning the ground into a featureless silicate dust.

They spoke of this. Teel murmured, ‘But the Qax were here only a few centuries.’

Dolo nodded. The silvery light reflected from the planes of his face; he was about fifty years old. ‘Much of this is human work, Coalition work. The Qax tried to destroy our past, to cut us adrift from history. Their motivation was wrong - but their methods were valid. Remember, we have been in direct conflict with the Xeelee for eleven thousand years. We have done well. We have swept them out of the plane of the Galactic disc. But they remain huddled in their fortress in the Core, and beyond our little island of stars they swarm in uncounted numbers. We must put the past aside, for it is a distraction. If the Xeelee defeat us, we will have no future - and in that case, what will the past matter?’

‘Your ideology is powerful.’

Dolo nodded. ‘A single idea powerful enough to keep mankind united across a hundred thousand light years, and through tens of millennia.’

Teel said, ‘But the mountains and rivers of Earth were far older than mankind. How strange that we have outlived them.’

Luca was startled by this anti-Doctrinal sentiment. Dolo merely looked interested, and said nothing.

The yacht soared upwards, out through the great ranks of Snowflake surveillance stations that stretched as far as Earth’s Moon, and the planet itself turned into a glistening pebble that fell away into the dark.

It would take them a day to reach Saturn. Luca, on this first trip out of Earth’s gravitational well, had expected to glimpse Earth’s sister worlds - perhaps even mighty Jupiter itself, transformed millennia ago into a gleaming black hole in a futile gesture of rebellion. But he saw nothing but darkness beyond the hull, not so much as a grain of dust, and even as they plunged through the outer system the stars did not shift across the sky, dwarfing the journey he was making.

Saturn itself was a bloated ball of yellow-brown that came swimming out of the dark. It was visibly flattened at the poles, and rendered misty in the diminished light of the already remote sun. Rings like ceramic sheets surrounded it, gaudy. The world itself was an exotic place, for, it was said, mighty machines of war had been suspended in its clouds, there to defend Sol system should the unthinkable happen and the alien foe strike at the home of mankind. But if the machines existed there was no sign of them, and Luca was disappointed when the yacht stopped its approach when the planet was still no larger than he could cover with his hand.

But Saturn wasn’t their destination.

Dolo murmured, ‘Look.’

Luca saw an artefact - a tetrahedron, glowing sky-blue - sailing past the planet’s limb. Kilometres across, it was a framework of glowing rods, and brown-gold membranes of light stretched across the open faces. Those membranes held tantalising images of star fields, of suns that had never shone over Saturn, or Earth.

‘A wormhole Interface,’ Luca breathed. It was like a dream of a forbidden past.

Wormholes were flaws in space and time which connected points separated by light years - or by centuries - with passages of curved space. On the scale of the invisibly small, where the mysterious effects of quantum gravity operated, spacetime was foam-like, riddled with tiny wormholes. It had taken the genius of the legendary engineer Michael Poole, more than twenty thousand years ago, to pull such a wormhole out of the foam and manipulate it to the size and shape he wanted: that is, big enough to take a spacecraft.

‘Once it must have been magnificent,’ Teel said now. ‘Poole and his followers built a wormhole network that spanned Sol system, from Earth to the outermost ice moon. At Earth itself wormhole gates of all sizes drifted across the face of the planet like sculptures.’ This evocation was surprisingly poetic. But then Teel had been brought up within the Core itself - you couldn’t get much further from Earth than that - and Luca wondered how much this trip to the home system meant to her.

But Dolo said sternly, ‘That was before the Occupation, of course. The Qax broke it all up, destroyed the Poole wormholes. But now we are building a mighty new network, a great system of arteries that runs, not just across Sol system, but all the way to the Core of the Galaxy itself. There are a thousand wormhole termini orbiting in these rings. And if we have that in the present, we don’t need dreams of the past, do we?’

Teel did not respond.

The yacht swept on, tracking the great ring system into the shadow of the planet.

Ships swarmed everywhere, pinpricks in the dark. Saturn, largest planet in the system now that Jupiter had been imploded, was used merely as a convenient gravitational mooring point for the mouths of the wormholes, tunnels through space and time. And its rings were being mined, ice and rock fragments hurled into the wormhole mouth to feed humans at remote destinations. Luca had heard mutterings in the seminaries at the steady destruction of this unique glory. In another couple of centuries, it was predicted, the ravenous wormholes would have gobbled up so much the rings would be barely visible, mere wraiths of their former selves. But, as Dolo would have remarked had Luca raised the point, if the victorious Xeelee caused the extinction of mankind, all the beauty in the universe would have no point, for there would be no human eyes to see it.

Now they were approaching a wormhole Interface. One great triangular face opened before Luca, wider and wider, until it was like a mouth that would swallow the yacht. A spark of light slid over the grey-gold translucent sheet that spanned the face, the reflected light of the yacht’s own drive.

Suddenly Luca realised that he was only moments from being plunged into a wormhole mouth himself, and his heart hammered.

Blue-violet fire flared, and the yacht shuddered. Fragments of the Interface’s exotic matter framework were already hitting the yacht’s hull. That grey-gold sheet dissolved into fragments of light that fled from a vanishing point directly before him. This was radiation generated by the unravelling of stressed spacetime, deep in the throat of the flaw. For the first time since they had left Earth there was a genuine sensation of speed, of limitless, uncontrollable velocity, and the yacht seemed a fragile, vulnerable thing around him, a flower petal in a thunderstorm.

Luca gripped a rail. Aware of Teel at his side he tried not to cower, to hide his head from the stretched sky which poured down over him.

After a few days of hyperdrive hops and falls through branching wormholes, they reached the Orion Line. This was the innermost section of the Galactic spiral arm which contained Earth’s sun. They emerged at a new clustering of wormhole Interfaces, a huge interchange that dwarfed the port at Saturn, carrying the commerce of mankind across thousands of light years.

Here they transferred to a Spline, a living thing transformed into a Navy warship. In the increasingly dangerous regions into which they would now venture, such protection was necessary.

Before they resumed their journey to the centre they took dinner, just the three of them, in a transparent blister set on the Spline’s outer hull. At their small table they were served, not by automata but by humans, Navy ratings who hovered with cutlery, plates, dishes, even a kind of wine. It was a surreal experience for Luca, for all around the table, outside the blister’s glimmering walls, the Spline’s epidermis stretched away like the surface of a fleshy moon, and beyond its close horizon wormhole mouths glimmered like raindrops.

Commissary Dolo seemed slightly drunk. He was holding forth about the history of the Orion Line. ‘Do you know the geography of the Galaxy, Novice? Look over there.’ He pointed with his fork. ‘That’s the Sagittarius Arm, the next spiral arm in from ours. The Silver Ghosts strove for centuries to keep us out of those lanes of stars.’ He talked on about the epochal defeat of the Ghosts and the thunderous Expansion since, and how the great agencies of the Coalition, the Navy, the Commission, the Guards, the Academies and the rest, had worked together to achieve those victories - and how officials like the Surveyor of Revenues and the Auditor-General laboured to maintain the mighty economic machine that fuelled the endless war - and, of course, how his own department within the Commission, the Office of Doctrinal Responsibility, oversaw the rest. He made it sound as if the conquest of the Galaxy was an exercise in paperwork.

As the Commissary talked, when he thought Dolo wasn’t watching him, Luca studied Teel.

There was something animal in her deft actions with her cutlery, the powerful muscles that worked in her cheeks. It was as if she could not be sure when her next meal would come. Everything she did was so much more solid and vivid than anything else in his life - and far more fascinating than the great star clouds that illuminated the human empire. He was thrilled that they shared this transient bubble of isolation.

When Dolo fell silent, Luca took his chance. He leaned subtly closer to Teel. ‘I suppose the food we eat is the same from one end of the Galaxy to the other.’

She didn’t look directly at him, but she turned her head. ‘Since this food comes from the belly of this Spline ship, and since the Spline are used all over the Galaxy - yes, I imagine you are right, Novice.’

‘But not everything is the same,’ he found himself babbling. ‘We are about the same age, but our two lives could hardly have been more different. There is much about you that I envy.’

‘You know very little about my life.’

‘Yes, but even so—’

‘What do you envy most?’

‘Comradeship. I was born in a birthing centre and placed in a cadre. That’s how it was for everybody. The cadres are broken up in cycles; you aren’t allowed to get too close to your cadre siblings. Even at the seminaries I am in competition with the other novices. Intimacy is seen as inevitable, but is regarded as a weakness.’

‘Intimacy?’

‘I have had lovers,’ he said, ‘but I have no comrades.’ He regretted the foolish words as soon as they were uttered. ‘At the Front, everybody knows—’

‘What everybody knows is always to be questioned, Novice,’ said Dolo. Suddenly he no longer seemed drunk, and Luca wondered if he had fallen into some subtle trap. Dolo turned in his chair, waving his empty glass at the attendant ratings.

When Luca looked back, Teel had turned away. She was peering at the Sagittarius Arm’s wash of light, as if with her deep eyes she could see it more clearly.

The Galaxy was a hundred thousand light years across, and over most of its span the stars were scattered more sparsely than grains of sand spread kilometres apart. On such a scale even the greatest human enterprise was dwarfed. And yet, as they neared the centre, the sense of activity, of industry, accelerated.

They moved within the 3-Kiloparsec Arm, the innermost of the spiral arms proper, wrapped tightly around the Core region. Here, no more than a few thousand light years from the Core itself, the Spline was replenished in orbit around a world that glistened, entirely covered in metal. This was a factory world, devoted to the production of armaments. Great clusters of wormhole mouths hovered over its gleaming surface, amid a cloud of Snowflake surveillance posts.

On a data desk, Dolo sketched concentric circles. ‘The Core itself is surrounded by our fortresses, our warrior worlds and cities. As you’ll see, Novice. Behind that, out here we are in the hinterland. Around a belt hundreds of light years thick, factory worlds churn out the material needed to wage the war. And behind that there is an immense and unending inward resource flow from across the Galaxy’s disc, a flow through wormhole links and freighters of raw materials for the weapons factories, the lifeblood of a Galaxy all pouring into the centre to fuel the war.’

‘It is magnificent,’ Luca breathed. ‘An organisation Galaxy-wide, built and directed by humans.’

‘But,’ Teel said dryly, ‘do you think the Galaxy even notices we are here?’

Again Luca was disturbed by her flirting with non-Doctrine.

Dolo laughed softly. He said to Luca, ‘Tell me what you have learned about our mission. Why are we here? Why was Captain Teel required to travel all the way out to Earth? What is there in this outbreak of faith so far from Earth that concerns us?’

What concerns me, Luca thought, is my relationship with Teel. But beyond that was his duty, of course; he aspired to become a Commissary, for the Commission for Historical Truth was the mind and conscience of the Third Expansion, and he did take his mission very seriously. ‘It is only the Druz Doctrines that unite us, that enable the efficient working of the Expansion. If even our front-line troops are allowed to waste energy on foolish non-Doctrinal maundering—’

‘Captain? What do you think?’

Teel pulled her lip, and Luca saw tiny hairs there, shining in the starlight. ‘I think there is more at stake here than mere efficiency.’

‘Of course there is. Perhaps I am training the wrong novice,’ Dolo said ruefully. ‘Luca, human history is not a simple narrative, a story told to children. It is more like a pile of sand.’

‘Sand?’

‘Heaped up,’ Dolo said, miming just that. ‘And as you add more grains - one at a time, random events added to the story - the heap organises itself. But the heap, the angle of the slope, is always at a state at which it is liable to collapse with the addition of just one more grain - but you can never know which grain. This is called “self-organised criticality”. And so it is with history.’

Luca frowned. ‘But the Coalition controls history.’

Dolo laughed. ‘None of us is arrogant enough to believe that we control anything - and certainly not the historical arc of a society spanning a Galaxy, even one as unified as ours. Even the foreknowledge of the future compiled by the Libraries is of no help. All we can do is watch the grains of sand as they fall.’

Luca found this terrifying, the notion that the great structure of the Expansion was so fragile. Equally terrifying was the realisation of how much knowledge he still had to acquire. ‘And you think the religious outbreak at the Core is one such destabilising grain?’

‘I’m hoping it won’t be,’ Dolo said. ‘But the only way to know is to go there and see.’

‘And stop the grain falling.’

‘And make the right decision,’ Dolo murmured, correcting him.

They left the factory world and passed ever inwards towards the Core, through more veils of stars.

At last they faced a vast wall of light. These were star-birthing clouds. Against the complex, turbulent background Luca could pick out globular clusters, tight knots of stars. Ships sailed silently everywhere, as deep as the eye could see. But from behind the curtain of stars and ships a cherry-red light burned, as if the centre of the Galaxy itself was ablaze.

Teel said, ‘We are already within the Core itself, strictly speaking. Surrounding the Galaxy’s centre is a great reservoir of gas some fifteen hundred light years across - enough to bake a hundred billion stars, crammed into a region smaller than that spanned by the few thousand stars visible to human eyes from Earth. That wall you see is part of the Molecular Ring, a huge belt of gas and dust clouds and star-forming regions and small clusters. The Ring surrounds the centre itself, and the Xeelee concentrations there.’

Dolo said evenly, ‘The Ring is expanding. It is thought that it was thrown off by an explosion in the Core a million years ago. We have no idea what caused it.’

‘How remarkable,’ Luca said. ‘In this dense place, this is the debris of an explosion: a great rolling wave of star birth. And what is that pink light that glows through the clouds?’

For the first time in the days since he had met her Teel looked directly at him. Her blue eyes seemed as wide as Earth’s oceans, and he felt his breath catch. ‘That,’ she said simply, ‘is the Front. By that light people are dying.’

Luca felt a complex frisson of fear and anticipation. All his life he had lived in a human space thousands of light years deep. He could look up into the sky and pick out any star he chose, and know that either humans were there, or they had been there and moved on, leaving the system lifeless and mined out. But now it was different. This slab of sky with its teeming clouds and young stars was not human. Up to now, he had been too concerned with his relationships with Teel and Dolo, and beyond that his duty, to have thought ahead. He realised he had no idea what he might find here at the Core, none at all.

He said reflexively, ‘ “A brief life burns brightly.” ‘

‘Here we have a different slogan,’ murmured Teel. ‘ “Death is life.” ‘

The Spline ship moved on, cautiously approaching the vast clouds of light.

II

The asteroid had an official number, even an uplifting name, provided by a Commissary on distant Earth. But the troopers who rode it just called it the Rock.

‘But then,’ Teel quietly told Luca, ‘they call every asteroid the Rock.’

And from this Rock’s surface, everything was dwarfed by the magnificent sky. They were very close to the Galaxy’s heart now, and the heavens were littered with bright hot beacons which, further out, merged into the clouds of light where they had been born. Beyond that was the curtain of shining molecular clouds that walled off the Galaxy’s true centre - a curtain through which cherry-red light poured unceasingly, a battle glow that had already persisted for centuries.

The three of them, with a Navy guard, were walking on the Rock’s surface in lightweight skinsuits. The asteroid was just a ball of stone some fifty kilometres across, one of a swarm that surrounded a hot blue-white star. The young sun’s low light cast stark shadows from every crater, of which there were many, and from every dimple and dust grain at Luca’s feet. He found himself fascinated by small details - the way the dust you kicked up rose and fell through neat parabolas, and clung to your legs so that it looked as if you had been dipped in black paint, and how some craters were flooded with a much finer blue-white powder that, somehow bound electrostatically, would flow almost like water around your glove.

But it was a difficult environment. His inertial-control boots glued his feet to the dusty rock, but in the asteroid’s microgravity his body had no perceptible weight, and he felt as if he was floating in some invisible fluid, stuck by his feet to this rocky floor - or, if he wasn’t careful about his sense of perspective, he might feel he was walking up a wall, or even hanging from a ceiling. He knew the others, especially Teel, had noticed his lack of orientation, and he was mortified with every clumsy glue-sticky step he took.

Meanwhile, all across the surface of this Rock, by the light of the endless war, soldiers toiled.

The troopers wore military-issue skinsuits, complex outfits replete with nipples and sockets and grimy with rubbed-in asteroid dirt. Some of the suits had been repaired; they had discoloured patches and crude seams welded into their surfaces. These patched-up figures moved through great kicked-up clouds of black dust, while machines clanked and hovered and crawled around them.

Most of the troopers’ heads were crudely shaved, a practicality if you were doomed to wear your skinsuit without a break for days at a time. With grime etched deep into their pores it was impossible to tell how old they were. They looked tired, and yet kept on with their work even so, long past the normal limits of humanity. They were nothing like the steel-eyed warriors Luca had imagined. They looked like experts in nothing but endurance.

It seemed to Luca that what they were basically doing was digging. Many of them used simple shovels, or even their bare hands. They dug trenches and pits and holes, and excavated underground chambers, each trooper, empowered by microgravity, hauling out huge masses of crumpled rock. Luca imagined this scene repeated on a tremendous swarm of these drifting rocky worldlets, soldiers digging endlessly into the dirt, as if they were constructing a single vast trench that enclosed the Galaxy Core itself.

Dolo made a remark about the patched-up suits.

Teel shrugged. ‘Suits are expensive here. Troopers themselves are cheaper.’

Luca said, ‘I don’t understand why they are digging holes in the ground.’

‘To save their lives,’ Teel said.

‘It’s called “riding the Rock”, Novice,’ Dolo said.

When it was prepared, Luca learned, this asteroid would be thrown out of its parent system, and in through the Molecular Ring towards the Xeelee concentrations. The first phase of the journey would be powered, but after that the Rock would fall freely. The troopers, cowering in their holes in the ground, would ‘run silent’, as they called it, operating only the feeblest power sources, making as little noise and vibration as possible. The point was to fool the Xeelee into thinking that this was a harmless piece of debris, and for cover many unoccupied rocks would be hurled in along similar trajectories. At closest approach to a Xeelee emplacement - a ‘Sugar Lump’ - the troopers would burst out of their hides and begin their assault.

‘It sounds a crude tactic, but it works,’ said Dolo.

‘But the Xeelee hit back,’ said Luca.

‘Oh, yes,’ Teel said, ‘the Xeelee hit back. The rocks themselves generally survive. Each time a rock returns we have to dig out the rubble, and build the trenches and shelters again. And bury the dead.’

Luca frowned. ‘But why dig by hand? Surely it would be much more efficient to leave it to the machines.’

Dolo said carefully, ‘The soldiers seem to believe that a shelter constructed by a machine will never be as safe as one you have dug out yourself.’

‘That doesn’t make sense,’ Luca said. ‘All that matters is a shelter’s depth, its structural qualities—’

‘We aren’t talking about sense,’ Dolo said. ‘We are touching here on the problem we have come to study. Come, Novice; recall your studies on compensatory belief systems.’

Luca had to dredge up the word from memory. ‘Oh. Superstition. The troopers are superstitious.’

Dolo said, ‘It’s a common enough reaction. The troopers have little control of their lives, even of their deaths. So they seek to control what they can - like the ground they dig, the walls that shelter them - and they come to believe that such actions in turn might placate greater forces. All utterly non-Doctrinal, of course.’

Luca snorted. ‘It is a sign of weakness.’

Teel said without emotion, ‘Imagine this Rock cracking like an egg. Sometimes that happens, in combat. Imagine humans expelled, sent wriggling defenceless into space. Imagine huddling in the dark, waiting for that to happen at any moment. Now tell me how weak we are.’

‘I’m sorry,’ Luca said, flustered.

Dolo was irritated. ‘You’re sorry, you’re sorry. Child, open your eyes and close your mouth. That way we’ll all get along a lot better.’

They walked on.

The horizon was close and new land ahead hove constantly into view, revealing more pits, more toiling soldiers. Luca had the disconcerting sensation that he was indeed walking around the equator of a giant hall of rock, and his vertigo threatened to return.

It was because he was so busy trying to master his queasiness that he didn’t notice the arch until they had almost walked under it. It was a neat parabola, perhaps twenty metres tall. A single trooper was standing beneath it, hands behind her back, stiffening to attention as Teel approached.

‘Ah,’ said Dolo, breathing a little heavily with the exertion of the suited walk. ‘So this is what we have come so far to see.’

Luca stood under the arch. Its fine span narrowed above him, making a black stripe across the complex sky. The arch was so smoothly executed that he thought at first it must have been erected by machine, perhaps from blown rock. But when he bent closer he saw that the arch was constructed from small blocks, each no larger than his fist, stone that had been cut and polished. On each block writing was etched: names, he saw, two or three on each stone.

Teel stood at one side of the arch, picked up a pebble of conglomerate, and with care lobbed it upwards. It followed a smooth airless arc that almost matched the arch’s span. ‘Geometrically the arch is almost perfect,’ she said.

Dolo bent to inspect the masonry. ‘Remarkable,’ he murmured. ‘There is no mortar here, no pinning.’

‘It was built by hand,’ Teel said. ‘The troopers started with the keystone and built it up side by side, lifting what was already completed over the new sections. Easy in microgravity.’

‘And the stone?’

‘Taken from deep within the asteroid - kilometres deep. The material further up has been gardened by impacts, shattered and conglomerated. They had to dig special mines to get to it.’

‘And all done covertly, all kept from the eyes of their commanders.’

‘Yes.’

Dolo turned to Luca. ‘What do you make of it, boy?’

Luca would have had to dredge for the word if he hadn’t been studying this specific area of deviancy. ‘It is a chapel,’ he said. A chapel of the dead, he thought, whose names are inscribed here. He glanced up at the arch’s span. There was writing up to the limits of his vision. Hundreds of names, then.

‘Yes, a chapel.’ Dolo walked up to the single trooper standing under the arch. She held her place, but returned the Commissary’s scrutiny apprehensively.

Teel said, ‘This is Bayla.’

‘The one on the charge.’

‘She faces a specimen charge of anti-Doctrinal behaviour. Similar charges will be applied to others of the unit here depending on the outcome of the hearing - on your decision, gentlemen.’

Dolo looked the trooper up and down, as if he could read her mind by studying her suited body. ‘Trooper. You understand the charge against you. Are you guilty?’

‘Yes, sir.’

‘Tell me about Michael Poole.’

Bayla was silent for a moment, visibly frightened; the visor of her skinsuit was misted. She glanced at Teel, who nodded.

And so Bayla stammered a tale of how the great engineer of ancient times, Michael Poole, had ridden one last wormhole to Timelike Infinity, the end of time itself. There he waited, watching all the events of the universe unfolding - and there he was ready to welcome those who remembered his name, and honour those who had fallen - and from there his great strength would reach out to save those who followed his example.

Dolo listened to this dispassionately. ‘How many times have you ridden the Rock?’

‘Twice, sir.’

‘And what are you most afraid of, trooper?’

Again Bayla glanced at Teel. ‘That you won’t let me back.’

‘Back where?’

‘To ride the Rock again.’

‘Why does that frighten you?’

Because she does not want to abandon her comrades, Luca thought, watching her. Because she is guilty to be alive where others have fallen around her. Because she fears they will die, leaving her to live on alone.

But Bayla said only, ‘It is my duty, Commissary. A brief life burns brightly.’

Teel said, ‘Simply say what you believe, trooper; it won’t help you to mouth slogans.’

‘Yes, sir.’

Luca walked back to the arch, for now Teel was standing under it, running her gloved hand over its surface. ‘It’s beautiful,’ he essayed.

She shrugged. ‘It’s a tribute, not a work of art. But yes, it is beautiful.’

After his foolish remark about weakness he wanted to rebuild his connection with her. ‘The names.’ He glanced up at the arrayed letters over his head. He said boldly, ‘To record the fallen may be non-Doctrinal, but here it seems - appropriate. If I had time I would climb this arch and count all the names.’

‘It might take you longer than you think.’

‘I don’t understand.’

She pointed to a name, inscribed in the surface before his face. ‘What do you see?’

‘ “Etta Maris”,’ he read. ‘A name.’

‘Now look at the first letter. Your suit visor has a magnification option; just tell it what you want to do.’

It took a couple of tries before he got it right. A Virtual flickered into existence before his face, the magnified letter. Even on this scale the carving was all but flawless - a labour of devotion, he saw, moved. But now he looked more closely, and he saw there were more names, inscribed within the carved-out grooves of the letter.

He stepped back, shocked. ‘Why, there must be as many names here, in this single letter, as are inscribed on the whole of the arch.’

‘I wouldn’t know,’ Teel said coolly. ‘Pick a name and look again.’

Again he magnified a single letter from one inscribed name - and again he found more names, thousands of them, crowded in far beneath the level of human visibility.

‘The names in the top layer were carved by hand,’ Teel said. ‘Then they used waldoes, and lasers, and ultimately replicator nanotech . . .’

He increased the magnification again and again, finding more layers of names nested one within the other. There were more layers than he could count, more names than could ever read if he stood here for the rest of his life. Just on this one Rock. And perhaps there were similar memorials on all the other bits of battered debris at every human emplacement, all the way around the core of the Galaxy, a great band of death stretching three thousand light years across space and two thousand years deep in time. He stepped back, shocked.

Teel studied his face. ‘Are you all right?’

His eyes were wet, he found. He tried to blink away the moisture, but to his chagrin he felt a hot tear roll down his cheek. It was a dark epiphany, this shock of the names.

‘I shouldn’t have to teach you the Doctrines,’ Teel said, comparatively gently. ‘We each have one life. We each die. The question is how you spend that life.’ She reached up with a gloved finger to touch his moist cheek - but her finger touched his visor, of course, and she dropped her hand and looked away, almost shyly.

He was astonished. In this brief moment of his own weakness, when he had been overwhelmed by something so much greater than he was, he had at last acquired some stature in her eyes; he had at last made the kind of contact with her that he had dreamed about since they had met.

After several hours on the surface they were escorted to what Teel called a bio facility, a pressurised dome where the soldiers could tend their bodies and their skinsuits, eat, drink, void their wastes, sleep, fornicate, play.

Around the perimeter of a central atrium there were small private cubicles, including dormitories, toilets and showers. Dolo and Luca were going to have to share one small, grimy compartment, at which Dolo scowled. Luca found a toilet and used it with relief. He had been unable to use the facilities in his skinsuit, in which you were just supposed to let go and allow the suit to soak it all up; it hadn’t helped that the suits were semi-transparent.

He wandered uncertainly through the large central area. Under its fabric roof the facility was too hot. There was a stink of overheated food from the replicator banks, and the floor was grimy with sweat and ground-in asteroid dirt. The troopers, dressed in dirty coveralls, walked and laughed, argued and wrestled. While Luca had kept his inertial-control boots on, the soldiers mostly went barefoot; they jumped, crawled, even somersaulted, at ease in the low gravity environment. Many of them were sitting in solemn circles singing songs, sometimes accompanied by flutes and drums that had been improvised from bits of kit. They played sentimental melodies, but Luca could not make out the words; the troopers’ vocabulary was strange and specialised, littered with acronyms.

There was graffiti on the walls. One crude sketch showed the unmistakable flared shape of a Xeelee nightfighter conflated with the ancient symbol of a fanged demon, and there were references by one sliver of a sub-unit to the incompetence and sexual inadequacy of the troopers in another, startlingly obscene. A couple of slogans caught his eye: ‘Love unto the utmost generation is higher than love of one’s neighbour. What should be loved of man is that he is in transition.’ And: ‘I am become Death, the Destroyer of Worlds.’ Another hand had added: ‘I am become Boredom, the Destroyer of Motivation.’

He joined Dolo on a small stage that had been set up before rows of seats. The daily briefing was soon to begin here. Luca reported on the graffiti he had seen. ‘I don’t recognise the sources.’

‘Probably pre-Occupation. Oh, don’t look so shocked. There is plenty of the stuff out there; we can’t control everything. In fact I think I recognise the first. Frederick Nietzsche.’ His pronunciation was strangulated.

‘It sounded a good summary of the Druz Doctrines to me.’

‘Perhaps. But I wonder how much harm those words have done, down across the millennia. Tell me what you think of our proto-religion here.’

‘The elements are familiar enough,’ Luca said. ‘The old legend of Michael Poole has been conflated with the beliefs of the Friends of Wigner.’ During the Qax Occupation the rebel group called the Friends had concocted a belief, based on ancient quantum-philosophical principles, that no event was made real until it was observed by a conscious intelligence - and hence that the universe itself would not be made real until all of its history was observed by an Ultimate Observer at Timelike Infinity, the very end of time. If such a being existed, then perhaps it could be appealed to - which was what the Friends had intended to achieve during their ultimately futile rebellion against the Qax. ‘It’s just that in this instance Poole himself has become that Observer.’

Dolo nodded. ‘Oddly, Michael Poole was lost in time - in a sense - his last act, so it is said, was to fly his ship deliberately into an unending network of branching wormholes, in order to save mankind from an invasion from the future. Perhaps he is still out there somewhere, wherever there is. You can certainly see the resonance of his story for these rock jockeys. Poole sacrificed his life for the sake of his people - and yet, transcendent, he lives on. What a role model!’ He actually winked at Luca. ‘I sometimes think that even if we could achieve a state of total purity, of totally blank minds cocooned from the history of mankind, even then such beliefs would start sprouting spontaneously. But you have to admit that it’s a good story.’ He sounded surprisingly mellow.

Luca was shocked. ‘But - sir - surely we must act to stop this drift from Doctrinal adherence. This new faith is insidious. You aren’t supposed to pray for personal salvation; it is the species that counts. If this kind of thing is happening all over the Front, perhaps we should consider more drastic steps.’

Dolo’s eyes narrowed. ‘You’re talking about excision.’

In the seminaries there had been chatter for millennia about the origin of the religious impulses which endlessly plagued the swarming masses under the Commission’s care. Some argued that these impulses came from specific features of the human brain. Thus perhaps the characteristic sense of oneness with a greater entity came from a temporary disconnection within the parietal lobe, detaching the usual sense of one’s self - controlled by the left side of this region - from the sense of space and time, controlled by the right. And perhaps a sense of awe and significance came from a malfunction of the limbic system, a deep and ancient system keyed to the emotions. And so on. If a mystical experience was simply a symptom of a malfunctioning brain - like, say, an epileptic fit - then that malfunction could be fixed, the symptoms abolished. And with a little judicious tinkering with the genome, such flaws could be banished from all subsequent generations.

‘A future without gods,’ said Luca. ‘How marvellous that would be.’

Dolo nodded. ‘But if you had had such an excision - and you had stood under the arch of names - could you have appreciated its significance? Could you have understood, have felt it as you did? Oh, yes, I watched you. Perhaps those aspects of our brains, our minds, have evolved for a purpose. Why would they exist otherwise?’

Luca had no answer. Again he was shocked.

‘Anyhow,’ said Dolo, reverting to orthodoxy, ‘tampering with human evolution - or even passively allow it to happen - is itself against the Druz Doctrines. We win this war as humans or not at all - and we bend that rule at our peril. We have stayed united, across tens of thousands of light years and unthinkably huge populations, because we are all the same. Although that’s not to say that evolution isn’t itself taking mankind away from the norm that Hama Druz himself might have recognised.’

‘Commissary?’

‘Well, look around you. Most of these soldiers are the children of soldiers - obviously, how could it be otherwise? And the relentless selection of war is working to shape a new kind of human, better equipped for the fight. Combat survivors are the ones who get to breed, after all. Already their descendants are wiry, lithe, confident in the three-dimensional arena of low or zero gravity. Some studies even suggest that their eyes are adapting to the pressure of three-dimensional combat - that some of them can see velocity, for example, by perceiving subtle Doppler shifts in the colours of approaching or receding objects. Think what an advantage that would be in the battlefield! Another few thousand years of this and perhaps we will not recognise the soldiers who fight for the rest of us.’

‘I think I’m losing my bearings,’ said Luca truthfully.

Dolo patted his shoulder. ‘No. You’re just learning, is all.’

‘And what have you learned about my troopers?’ Teel had joined them on the small stage, and the troopers began to line up in rows before them.

Luca had learned to be honest with her. ‘I find them - strange.’

‘Strange?’

‘They have all ridden the Rock, yes?’

‘Most of them.’

‘Then they have seen comrades fall. They know they will be sent out again to a place where they must face the same horror. And yet, here and now, they laugh.’

Teel thought about that and answered carefully. ‘Away from the Front you don’t talk about what happens out there. It’s like - a secret. You’ve seen something beyond normal human experience. If you show your fear, or even admit it to yourself, then you’re allowing a leak between this, normal human life, and what lies out there. You’re letting it in. And if that happens there will be nowhere safe. Do you understand?’

He watched her face; there was sweat on her brow, traces of asteroid grime. ‘Is that how you feel?’

‘I try not to feel anything,’ she said.

Luca looked around the dome. ‘And this place is so shabby.’ He felt a kind of self-righteous anger, and he encouraged it in himself, hoping to impress Teel. ‘If these people are willing to die for the Expansion, they should have some comfort.’

Dolo shook his head. ‘Again you don’t understand, Novice. Think about the life of a soldier. It is a limited existence: moments of birth and growth, comradeship, determination, isolation - and finally, after the briefness of the light, an almost inevitable conclusion in pain and death. They have to know they are fighting for something better. And so they have to see that the present is imperfect. The soldiers must live in an eternal now of shabbiness and toil, so that they can be made to believe that we will progress from such places until a glorious victory is won, and everything will be made perfect - even if no such progress is ever actually made.’

‘Then everything here is designed for a purpose,’ Luca said, wondering. ‘Even the shabbiness.’

‘This is a machine built for war, Novice.’

A junior officer called the troops to order. On their crude seats, just blocks of asteroid rock, they fell silent.

Teel stood up. She said clearly, ‘Eighteen thousand, three hundred and ninety-one years ago an alien force conquered humanity’s home planet. We are here to ensure that never happens again.’ She held up a data desk and read a single short obituary, a summary of one ordinary soldier’s life and death. Here was another memorial, Luca supposed, for those who had fallen - and again, not strictly Doctrinal. Then Teel went on to a kind of situation report, summarising incidents from right around the Molecular Ring that circled the Galaxy’s centre.

The troops listened carefully. Luca watched their faces. Their gazes were fixed on Teel as she spoke, their mouths open like rapt children’s, some of them even quietly echoing the words she used. When she finished - ‘Let’s hurl the Xeelee starbreakers down their own Lethe-spawned throats!’ - there was cheering, and even some tears.

Teel invited Dolo to get to his feet. As an emissary of the Coalition, he was to make a short address to these far-from-home troopers. He was greeted with whistles and foot-stamping. Luca thought he looked small and out of place in his pristine Commissary’s robe.

Dolo talked in general terms about the war. He said that the ‘Ring theatre’ was a testing ground for future operations, including the eventual assault on the Xeelee concentrations in the Core itself - which, he hinted, might be closer than anybody expected. ‘This a momentous time,’ he said, ‘and you have a momentous mission. You have been commissioned by history. This is total war. Our enemy is implacable and powerful. But if we let our vision of the universe and ourselves go forth, and we embrace it entirely, those who remember us will sing songs about us years from now . . .’

Luca let the words slide through his awareness. When the troops dispersed he found a way to get close to Teel.

She said, ‘So do you think you have seen the comradeship you envied so much?’

‘They love you.’

She shook her head. ‘They think I’m a lucky commander. I’ve ridden this Rock four times already, and I’m still in one piece. They hope I’ll give them some of my good fortune. And anyhow they have to love me; it’s part of my job description. They won’t let their brains be blown out for a stuffed shirt—’

‘No, it’s more than that. They will follow you anywhere.’ His blood surging, longing to be part of her life, he said recklessly,

‘As would I.’

That seemed to take her aback. ‘You don’t know what you’re saying.’

He leaned closer. ‘You’ve known there is something between us, a connection deeper than words, since the moment we met—’

But here was Dolo, and the moment was already over. The Commissary held up a small data desk, ‘Novice, tomorrow we have a chance to advance your education. We will accompany a press gang.’

‘Sir?’

‘Be ready early.’

Teel had taken advantage of the interruption to slip away to join her troops. Luca saw how her face lit up when she spoke to those with whom she had fought. He was hopelessly jealous.

Dolo murmured, ‘Don’t lose yourself in her, Novice. After tomorrow, we will see if you still envy these troopers.’

III

The blue planet came swimming out of the dark.

Dolo said, ‘You know that planets are rare here. This close to the Core, with so many stars crowding, stable planetary orbits are uncommon. All the unformed debris, which elsewhere might have been moulded into worlds, here makes up huge asteroid belts - which is why the rocks are used as they are; they are plentiful enough.

‘This pretty world, though, was discovered by colonists of the Second Expansion - oh, more than twenty thousand years ago. Almost inevitably, they call it New Earth: names of colonised planets are rarely original. They brought with them a very strange belief system and primitive technology, but they made a good fist of terraforming this place. It lies a little close to its sun, though . . .’

Luca didn’t feel able to reply. The world was like a watery Earth, he thought, with a world-ocean marked by tiny ice caps at the poles and a scatter of dark brown islands. He felt unexpectedly nostalgic.

Dolo was watching his face. ‘Remember, though you are a Novice, you represent the Commission. We are the ultimate source of strength for these people. Keep your fear for the privacy of your quarters.’

‘I understand my duty, sir.’

‘Good.’

The yacht slid neatly into the world’s thick air. Under a cloud-littered blue sky the ocean opened out into a blue-grey sheet that receded to a misty horizon.

The yacht hovered over the largest archipelago, a jumble of islands formed from ancient and overlapping volcanic caldera, and settled to the ground. It landed in a Navy compound, a large complex marked out in bright Navy green and surrounded by a tall fence. Beyond the fence, the rocky land rolled away, unmodified save for snaking roads and scattered farms and small villages.

Luca and Dolo joined a handful of troopers in an open-top skimmer. Hovering a couple of metres above the ground the skimmer shot across the Navy compound - Luca glimpsed bubble domes, unpressurised huts, neat piles of equipment - and then slid through a dilating entrance in the outer wall and hurtled over the countryside.

They had to wear face masks. Even after twenty thousand years of terraforming of this world, there was still not enough oxygen in the air; it had taken half that time just to exterminate most of the native life. But they could leave their skinsuits behind, and Luca welcomed the feeling of sunlight on his exposed skin.

Dolo said, over the wind noise, ‘What you’re going to see is where many of those troopers you envy come from.’

Luca said, ‘I imagined birthing centres.’ Like the one into which he had been born, on Earth.

‘Yes. The children of soldiers are incubated in such places. But you’ve seen yourself that there is a - drift - in such populations, under the relentless selection pressure of combat. It’s a good idea to freshen up the gene pool with infusions of wild stock.’

‘Wild? Commissary, what is a “press gang”?’

‘You’ll see.’

The skimmer arrived at a village by the coast.

Luca stepped out of the hovering vehicle. The volcanic rock felt lumpy through the thin soles of his boots. A harbour, a rough crescent shape, had been blasted into the rock, and small boats bobbed languidly on oily water. Even through the filters in his mask Luca could smell the intense salt of the sea air, and the electric tang of ozone. But the volcanic rock was predominantly black, as were the pebbles and sand, and the water looked eerily dark.

He looked back along the coast. Dwellings built of volcanic rock were scattered along a road that led back to a denser knot of buildings. Here and there green flashed amidst the black - grass, trees, Earth life struggling to prosper in this alien soil. It was clear these people fed themselves through agriculture: crops grown on the transformed land, fish harvested from the seeded seas. The Second Expansion had occurred before the Qax had brought effective replicator technology to Earth, an unintended legacy which still fed the mass of the human population today. And so these people farmed, a behavioural relic.

From the doorway of the nearest house a child peered out at him, a girl aged about ten, finger thrust into one nostril, wide-eyed and curious. She wore no mask; the locals were implanted with respiratory equipment at birth.

He said, wondering, ‘This is not a Coalition world.’

‘No, it is not,’ said Dolo. ‘Ideally all human beings, across the Galaxy, would think exactly the same thought at every moment; that is what we must ultimately strive for. But out here on the fringe of the Expansion, where resources are limited, things are - looser. The three million inhabitants here have been left to their own devices - such as their own peculiar form of government, which lapsed into a kind of monarchy. The war against the Xeelee is a priority over cleansing the minds of a few fisher-folk on a dirt ball like this.’

‘As long as they pay their taxes.’

Dolo grinned at him. ‘An unexpectedly cynical remark from my idealistic young Novice! But yes, exactly so.’

They walked with the troopers towards the house. The little girl disappeared indoors. Luca could smell cooking, a baking smell like bread, and a sharper tang that might have been some kind of bleach. Simple domestic smells. Flowers adorned the top of the doorway, a colourful stripe, and two small bells dangled from the door itself, too small to be useful as a signal to the occupants, a cultural symbol Luca couldn’t decode. The troopers in their bright green uniforms looked strikingly out of place, the shapes and colours all wrong, as if they had been cut out of some other reality and inserted into this sunlit scene.

There is a whole world here, Luca thought, a society which has followed its own path for twenty thousand years, with all the subtlety and individuality that that implies. I know nothing about it, had never even heard of it before coming here into the Core. And the Galaxy, which I as a Commissary will presume to govern, must be full of such places, such worlds, shards of humanity scattered over the stars.

A woman came to the door - the little girl’s mother? - strong-faced, about forty, with hands grimy from work in a field, or garden. She looked resigned, Luca thought on first impression. Her gaze ran indifferently over the Commissaries, and she turned to the lead trooper.

She spoke a language he didn’t recognise. The artificial voice of the trooper’s translating desk was small and tinny.

Luca said, ‘They must have brought their language with them. This woman speaks a relic of a pre-Extirpation tongue.’ He felt excited, intellectually. ‘Perhaps that aboriginal tongue could be reconstructed. Populations are scattered on this island world, isolated. Their languages must have diverged. By comparing the dialects of different groups—’

‘Of course that would be possible,’ said Dolo, sounded vaguely irritated. ‘But why would you want to do such a thing?’

Now the woman pressed her hand against the trooper’s data desk, a simple signature, and she called a name. The little girl came back to the door. She was a thin child with an open, pretty face; she looked bewildered, not scared, Luca thought. The mother reached down and gave the girl a small valise. She placed her hand on the girl’s back, as if to push her to the troopers.

Luca understood what was happening a moment before the girl herself. ‘We are here to take her away, aren’t we?’

Dolo held up a finger, silencing him.

The girl looked at the tall armour-clad figures. Her face twisted with fear. She threw down the valise and turned to bury her face in her mother’s belly, yelling and jabbering. The mother was weeping herself, but she tried to pull the child away from her legs.

‘She’s just a child,’ Luca said. ‘She doesn’t want to leave her mother.’

Dolo shrugged. ‘Child or not, she should know her duty.’

At first the troopers seemed tolerant. They stood in the sun, watching impassively as the mother gently cajoled the child. But after a couple of minutes the lead trooper stepped forward and put his gloved hand on the girl’s shoulder. The girl squirmed away. The trooper seemed to have misjudged the mother’s mood, for she jabbered angrily at him, pulled the child inside the house and slammed the door. The troopers glanced at each other, shrugged wearily, and fingered the weapons at their belts.

Dolo tugged Luca’s sleeve. ‘We don’t need to see the resolution of this little unpleasantness. Come. Let me show you what will happen to that child.’

The lead trooper agreed that Dolo could take the skimmer if a replacement was sent out. So Luca climbed back into the skimmer alongside Dolo, leaving the harbour village behind them. It did not take long before they were back within the enclosing wall of the Navy compound, with the complex disorderly local world of sea and rock and light shut out. Luca felt a huge relief, as if he had come home.

Dolo directed the skimmer to a cluster of buildings huddled within the wall. These blocky huts had been set around a rectangle of cleared ground, and fenced off from the rest of the Navy base. Once inside this compound within a compound, Dolo and Luca got out of the skimmer and walked across obsessively swept dirt.

Everywhere Luca could see children. They were of varying ages from ten or so through to perhaps sixteen. One group marched in formation, another was lined up in rows, a third was undergoing some kind of physical training over a crude obstacle course, a fourth was standing in a rough square, watching something at the centre. Luca imagined this place must be big enough to hold a thousand children, perhaps more.

‘What is this place?’

‘Call it a school,’ Dolo said. ‘Keep your eyes open; listen and learn. And remember—’

‘I know. I am the Commission. I mustn’t show what I feel.’

‘Better yet that you should feel nothing inappropriate in the first place. But not showing it is a start. First impressions?’

‘Regularity,’ Luca said. ‘Straight lines everywhere. Everything planned, everything ordered. Nothing spontaneous.’

‘And the children?’

Luca said nothing. There was silence save for barked commands; none of the children seemed to be saying anything.

Dolo said, ‘You must understand that children brought in from the wild are more difficult to manage than those raised in birthing centres from soldier stock, for whom the war is a way of life; they know nothing else. These wild ones must be taught there is nothing else. So they will spend six or more years of their lives in places like this. Of course past the age of thirteen - or younger in some cases - they are used in combat.’

‘Thirteen?’

‘At that age their usefulness is limited. Those who survive are brought back for further training, and to shape the others. It helps them become accustomed to death, you see, if they are returned from the killing fields to a place like this, which keeps filling up with more people, people, people, so that mortality becomes trivial, a commonplace of statistics . . . Here now; this is where that pretty little girl from the coast will be brought, when the troopers extract her from her clinging mother.’

It was a nondescript building, before which children had been drawn up in rows. Male and female, no older than ten or eleven, they were dressed in simple orange coveralls, and were all barefoot. A woman stood before them. She had a short club in her hand. The children’s posture was erect, their heads held still, but Luca could see how their eyes flickered towards the club.

One child was called forward. She was a slim girl, perhaps a little younger than the rest. The woman spoke to her almost gently, but Luca could hear she was describing, clinically, some small crime to do with not completing laundry promptly. The girl was wide-eyed and trembling, and Luca, astonished, saw urine trickle down her leg.

Then, without warning, the woman drew her club and slammed it against the side of the child’s head. The child fell in the dust and lay still. Luca would have stepped forward, but Dolo had anticipated his reaction and grabbed his arm. Immediately the woman switched her attention to the others. She stepped over the prone form and walked up and down their rows, staring into their faces; she seemed to be smelling their fear.

Luca had to look away. He glanced up. The Galaxy’s centre glowed beyond a milky blue sky.

Dolo murmured, ‘Oh, don’t worry. They know how to do such things properly here. The child is not badly hurt. Of course the other children don’t know that. The girl’s crime was trivial, her punishment meaningless - save as an example to the others. They are being exposed to violence; they have to get used to it, not to fear it. They must be trained not to question the authority over them. And—ah, yes.’

The woman had pulled a boy out of the ranks of silent children. Luca thought she could see tears glistening in his round eyes. Again the woman’s club flashed; again the child fell to the ground.

Luca asked, aghast, ‘And what was his crime?’

‘He showed feelings for the other, the girl. That too must be programmed out. What use would such emotions be under a sky full of Xeelee nightfighters?’ Dolo studied him. ‘Luca, I know it is hard. But it is the way of the Doctrines. One day such training may save that boy’s life.’

They walked on, as the children were made to pick up their fallen comrades.

They came to a more ragged group of children. Some of these were older, Luca saw, perhaps twelve or thirteen. It disturbed him to think that there might actually be combat veterans among this group of barefoot kids. At the centre of the group, two younger children - ten-year-olds - were fighting. The others watched silently, but their eyes were alive.

Dolo murmured, ‘Here is a further stage. Now the children have to learn to use violence against others. The older ones have been put in charge of the younger. Beaten regularly themselves, now they enjoy meting out the same treatment to others. You see, they are forcing these two to fight, perhaps just for entertainment.’

At last one of the fighters battered her opponent to the ground. The fallen child was dragged away. The victor was a stocky girl; blood trickled from her mouth and knuckles. One of the older children walked into the crude ring, grinning, to face the stocky girl.

Dolo nodded with a connoisseur’s approving glance. ‘That fighter is strong,’ he said. ‘But now she will learn afresh that there are many stronger than she is.’

‘These barefoot cadets must long to escape.’

‘But their prison is not just a question of walls. In some places the regime is - harsher. When they are taken from their homes, the children are sometimes made to commit atrocities there.’

‘Atrocities?’

Dolo waved a hand. ‘It doesn’t matter what. There are always criminals of one class or another who require corrective treatment. But after committing such an act the child is instantly transformed, in her own heart, and in the hearts of her family. The family may not even want the child back. So she knows that even if she escapes this place, she can never go back home.’ He smiled. ‘Ideally, of course, it would be a family member who is struck down; that would be the purest blow of all.’

‘How efficient.’

‘Even in the face of violence a child’s social and moral concepts are surprisingly resilient; it takes a year or more before such things as family bonds are finally broken. After that the child crosses an inner threshold. Her sense of loyalty - why, her sense of self - becomes entwined not with her family but with the regime. And, of course, the first experience of combat itself is the final threshold. After that, with all she has seen and done, she cannot go home. She has been reborn. She doesn’t even want to be anywhere else.’

They walked on to the edge of the compound. Beyond the rows of buildings there was a break in the fence. On the rocky plain beyond, a group of children, with adult overseers, were lying on their bellies in crude pits dug into the ground. They were working with weapons, loading, dismantling, cleaning them, and firing them at distant targets. The weapons seemed heavy, dirty and noisy; every firing gave off a crack that made Luca jump.

Dolo asked, ‘Now. Do you see what is happening here?’

‘More indoctrination. The children must be trained to handle weapons, to deploy destructive forces - and to kill?’

‘There are native animals - flying, bird-like creatures - which they hunt. These days the animals are raised for that purpose, of course; it has ironically saved them from extinction. Yes, they must learn to kill.’

‘And people?’

‘The Xeelee are not like us - but they are sentient. Therefore it helps to be exposed to the moral conflict of killing a sentient creature, before it is necessary to do it to save one’s life. So, yes, people too, when appropriate.’

‘Commissary, must we commit such barbarism to wage our war?’

Dolo looked surprised. ‘But there is no barbarism here. Novice, what did you expect? This regime, this crude empire of mud and clubs and blood, is actually a sophisticated processing system. It turns human beings, children, into machines.’

‘Then why use human beings at all? Why not fight the war with machines?’ It shocked him to find himself even mouthing such ideas.

Dolo seemed patient. ‘This is a question everybody must ask at least once, Luca. We fight as we do because of the nature of our foe, and ourselves. The Xeelee are not like humans, not even like species such as the Silver Ghosts, our starfaring rivals in the early days of the Expansion. Read your history, Novice. With the Xeelee there has never been a possibility of negotiation, diplomacy, compromise. None. In fact there has been no contact at all - other than the brutal collision of conflict. The Xeelee ignore us until we do something that disturbs them - and then they stomp on us hard, striking with devastating force until we are subdued. To them we are vermin. Well, the vermin are fighting back.’

‘And we are doing so,’ Luca said, ‘by consuming our children.’

‘Yes, our children - our human flesh and blood. Because that is all we have.’ Dolo held up his hands and flexed his fingers in Galaxy light. ‘We weren’t designed for waging a Galactic war - as the Xeelee seem to have been. We carry our past in our bodies, a past of cowering in trees, of huddling on plains, without weapons, without even fire to protect us, as the predators closed. But we fought our way out of that pit, just as we’re fighting our way out of this one - not by denying our nature but by exploiting it, by breeding, breeding, breeding, filling up every empty space with great swarms of us. We are nothing but flesh and blood - but in overwhelming numbers even soft flesh can win the day. Our humanity is our only, our final weapon, and that is how we will win.’ As he talked his broad face was alive with a kind of pleasure.

Around Luca the squads of children went through their routine of training, punishment, reward and abuse, their young minds shaped like bits of heated metal. He conjured up the face of Teel, her soft humanity above the stiff collar of the military uniform.

Dolo was watching him again. ‘You’re thinking of the lovely Captain. This is where she came from.’ He waved a hand. ‘An inductee into this dismal boot camp, here on New Earth, she was a tough fighter. Saw her first action at twelve, survived, went back for more. Why do you think I brought you here?’

Luca, bewildered, looked down at the dirt.

Dolo, at random, beckoned a small boy standing in a row of others. With a glance at his overseer the boy came running and stood at attention before them. His eyes were bright, lively. Dolo bent down and smiled. ‘Do you know who we are?’

‘No, sir,’ snapped the boy.

‘Then who are you?’

‘Who I am does not matter. Sir,’ he appended hastily.

‘Good. Then what are you?’

‘I am a little boy now, and I must study. But when I am big enough to operate a weapon I will join the unending war, and avenge those who have fallen, and fight for the future of mankind.’

Dolo straightened up. Luca would have sworn he could see a tear in his eye. ‘Novice, it has taken us twenty thousand years - perhaps even longer - to get to this point. But, step by step, we are reaching our goal. I give you the child soldier: the logical future of mankind.’

When Dolo nodded dismissal the boy turned away and walked back to his section. Luca could see he was struggling to contain his youthful energy, trying not to skip or run.

When they got back to the Rock, an evacuation and hasty re-equipping was underway. Non-combatants were removed from the Rock, equipment, stores and people hurried underground, weapons, sensor and drive emplacements rapidly completed and tested. Meanwhile the troopers were checking their skinsuits and other kit, and injecting themselves with mnemonic fluid, a record which might help the military analysts reconstruct whatever happened to them.

It turned out that orders had been changed. The Rock was to be hurled on its new mission to the Front in just a few more days, weeks ahead of the old schedule. Perhaps, Luca thought with a shiver, the prognosticating librarians on distant Earth had discerned some shifting in their misty maps of the future, and the Rock was to be sent to secure some famous preordained victory - or to avert some predetermined disaster.

But for him the most important consequence of this chain of events was that he was to be taken off the Rock and flown out to another station, while Teel was to ride the Rock once more to the Front itself.

He hurried to her quarters.

Aside from a small bathroom area there were just two pieces of furniture, a simple bed and table. She was sitting on the bed studying a data desk. The top button of her uniform was undone; he found his eyes drawn to the tiny triangle of flesh that showed there.

She put down the desk. ‘I knew you would come.’

‘You did?’

‘You have learned about the new orders. Your emotions are confused.’

Tentatively he sat beside her on the bed. ‘I’m not confused. I don’t want to be parted from you.’

‘Do you think I should defy my duty? Or you yours?’

‘No. I just don’t want to lose you.’

Her blue eyes were wide, deep as oceans. ‘It’s not that. You’ve been to New Earth. Now you know where I come from - what I am. You want to save me, don’t you?’

He was hot, miserable, perplexed. ‘I can’t tell if you are mocking me.’

She took his hand and enclosed it in hers. ‘Go home.’

‘Take me with you,’ he said.

‘What?’

It was as if he was framing the thoughts even as the words emerged from his mouth. ‘To the Front. Give me a posting on the Rock.’

‘That’s absurd. You’re a Commissary - a Novice at that. You don’t have the training.’

He let his voice harden. ‘I could surely be as useful as the twelve-year-old conscripts who will be riding with you.’

‘Do you know what you will face?’

‘I know you will be there.’ He moved his face closer to hers, just a little, until he could feel her breath on his mouth. It was his last voluntary act.

Her passion was primal, like the way she ate, as if after this moment there would be no more to savour. And all through the love-making, and the hours later they spent asleep together, he could sense the strength in her - a strength she held back, as if afraid of damaging him.

IV

Luca huddled at the bottom of the trench. It was just a gouge scraped roughly in the surface of the Rock.

He stared up at a great stripe of sky that was full of cherry-red light, a sky where immense rocks sailed like clouds. Sometimes they came so close to his own Rock he could actually see people moving on their inverted surfaces. It seemed impossible that such vast objects could be crowded so close. The slightest touch of one of these great jostling rocks against another could crush him and these shallow trenches and chambers, utterly erasing him and any trace to show he had ever existed, scraping clean his life from the universe. He was in a heavily armoured skinsuit, but he felt utterly defenceless. He was just a mote of soft blood and flesh, trapped in this nightmare machinery of churning rock and deadly light.

All of this in utter, inhuman silence, save for the shallow scratch of his own breathing, the constant incomprehensible chatter over his comms.

The Rock itself was a swarm of continual, baffling activity. Troopers crowded constantly past him, great files of them labouring from place to place carrying equipment and supplies. They were blank-faced, dogged, their suits carefully dusted with asteroid dirt in the probably vain hope that such camouflage would help them survive. Sometimes they stepped on Luca’s feet or legs, and he cowered against the dirt in his trench, trying to make himself small and invisible.

Bayla, the trooper on the charge of religious sedition, was with him, though. She had been assigned by Teel to ‘supervise’ him. Luca hadn’t seen anything of Teel herself since they had broken through the last cordon of Navy Spline ships and into the full battle light, and the final preparations had begun. Whatever fantasies he had had of working alongside Teel, of somehow participating in this effort, had long evaporated. The only human comfort he drew was from the warm pressure of Bayla’s leg against his own.

Bayla kept checking a chronometer and consulting lists that scrolled over the surface of her skinsuit sleeve. But every few minutes she took the time to check on Luca. ‘Are you all right?’

‘Yes.’ Again he had to push back to let a file of troopers past. ‘I don’t understand how they can do their jobs.’

‘What else is there to do?’

‘They must be afraid.’

He could see her frown. ‘You learn to live with the fear. Like living with an illness.’

‘A fear of death, or injury?’

‘No, not that.’ She spoke slowly. She seemed serene. ‘It’s more that it might not make sense. You feel you’re in the wrong world, the wrong time. That it shouldn’t be like this. If you let that in, that’s the true fear.’

He didn’t understand, of course.

A patch of Bayla’s sleeve flashed orange. ‘Excuse me.’ Bayla barked a command.

A file of troopers came scurrying through the dirt and took their position. They were carrying tools, he saw. The troopers all seemed small, light. Young, he realised. Bayla held up her hand, checked the time again - then brought her arm down in a chop. The troopers swarmed up over the side of the trench, using rungs and cables or just footholds gouged into the harder rock.

In response, light stormed.

Some of the troops fell back immediately, limp, like dolls. The rest of the troopers flattened themselves on their bellies in the dirt, under the light, and began to crawl away, face down, out of Luca’s sight. Other troopers came scurrying along the trench with med cloaks. They wrapped up the fallen and took them away, limp bundles that were awkward to handle in the low gravity.

There was a swirl of cubical pixels before Luca. It coalesced into the compact form of Dolo. He wasn’t wearing a skinsuit, and his robe was clean. In this place of dirt and rock and fire he was like a vision of an unattainable paradise. He smiled. ‘How are we bearing up, Novice?’

Luca found it difficult to speak. ‘Those troopers who went out of the trench in the first wave. They were children.’ Perhaps some of them had come from the induction camp on New Earth.

‘Think of it in terms of efficiency. They are agile, easy to command. But they are poor soldiers. They suffer higher casualty rates than their adult counterparts, in part because their lack of maturity and experience leads them to take unnecessary risks. And their young bodies are more susceptible to complications if injured. But little has yet been invested in their training.’

‘So they are expendable.’

‘We are all expendable,’ Dolo said. ‘But some are more expendable than others. They will not suffer, Luca: if it comes, death here is usually rapid. And if they see their fellows fall they will not grieve; their childish empathy has been beaten out of them.’ The Virtual floated closer to Luca, studying his face, close enough for Luca to see the graininess of the pixels. ‘You are still thinking this is inhuman, aren’t you? The evolution of your conscience is proving a fascinating study, Novice. Of course it is inhuman. All that matters are the numbers, the rates of mortality, the probabilities and cost of success. This is a statistical war - as wars have always been.’

There was a piercing whistle-like blast over the comms unit. Virtual Dolo popped out of existence, grinning.

A few of the child soldiers scrambled back over the trench’s lip - a very few, and several of them were nursing injuries. More troops came scurrying like files of rats along the trench. Soon there was a double line of them, most carrying hand weapons or tools, peering up at the sky.

For a few heartbeats everybody was still, waiting.

Bayla was beside Luca, as intent as the rest. Luca whispered to her, ‘What was the last thing you did before we left the bio facility?’

‘I sent my daughter a Virtual.’

A daughter. Sons and daughters, like family life in general, were strictly anti-Doctrinal. ‘Where is she?’

‘On New Earth. I told her how as a baby she laughed when she looked at my face. How she slept in my arms, how we bathed together. I told her that when she grows up and wants to know about me she should ask her father or her aunt. Whatever becomes of me, she must never think of herself as a child without a mother. I will always be watching her.’

‘From your place at Timelike Infinity,’ he hazarded.

‘I want her to be good, and to be the kind of person others would like. But I told her I was sorry that I had been a poor mother, an absent mother. When she was very small she had a doll, a soldier. I carry it with me as a good-luck charm.’ She patted her dust-covered tunic. Luca saw a slight bulge there. ‘This way she is always with me. The last time I saw her was during my last leave on New Earth. She was with the other children. They lined up to wave flags and sing for us. It’s burned in my mind, her face that day. I told her that when she hears of my death she should be happy for me, for I will have achieved my ambition.’

‘You embrace death, but you dream of your family.’

Bayla glanced at him. ‘What else is there to do?’

Another piercing shriek in Luca’s comms unit. No, it was a word, he realised, a word yelled so loud it overwhelmed the system itself. In response there was a muffled roar - more voices, thousands of voices, shouting together, maybe every trooper on the Rock.

Bayla raised her hand again, watching lights flash on her sleeve. ‘Wait, wait.’ The cherry-red light in the sky was growing brighter, shading to pink. It was like a silent, gathering sunrise, as if the Rock was turning to face some vast source of heat, and the noise rose in response.

Bayla brought her arm chopping down.

The first row of troopers swarmed forward, struggling to get out of the trench. Red light flared. Most of them fell back immediately, broken, limp, gases venting from ruined suits, and the yelling was broken now by screams of pain. Without hesitation the second line pushed after the first. They trampled on the fallen bodies of their comrades, even those who still moved, pushing their way over flesh and dirt to get to the lip of the trench. But they fell back in their turn, as if their bodies were exploding. Yet another line of troopers gathered and began to rush over the lip of the trench.

Suddenly Luca felt swept up, as if a great tide of blood was lifting these yelling troopers into battle. Without conscious thought he tore at the dirt with clumsy hands and hoisted his body out of the trench.

He was standing in a flood of light. Hardly anyone was standing with him, of the hundreds who had gone before him. There was a huddled heap of skinsuit every few paces, and bodies drifted helplessly above like moons of this asteroid, out of contact with the surface, to be pierced by relentless flickering beams of crimson light. When he looked back he saw that still another wave of troops was coming out of the trench. They were twitching like dolls as the darting light threaded through them. Soon the next wave were struggling to advance through a space that was clogged with corpses.

Space was sewn with cherry-red beams, a great flat sheet of them that flickered, vanished, came again. When he looked up he could see more of the beams, layer on layer, absolutely straight, that climbed up like a geometrical demonstration. The light crowded space until it seemed there wasn’t room for it all, that the beams must start to cut and destroy each other.

And still people fell, all around him. He had never imagined such things were possible. It was as if he had been transported into some new and unwelcome reality, where the old physical laws didn’t apply—

Somebody punched him in the back.

With agonising slowness, he fell to the dirt. Something landed on top of him. It wasn’t heavy, but he could feel how massive it was; its inertia knocked the wind out of him. For an instant he was pressed face down, staring at the fine-grained asteroid soil and the reflection of his own hollow-eyed face. But still the cherry-red light dazzled him; even when he closed his eyes he could see it.

He twisted and thrashed, pushing the mass off his back. It was a trooper, he saw. She was struggling, convulsing. A crater had been torn in her chest. Blood was gushing out, immediately freezing into glittering crystals, as if she was just pouring herself out into space. Her eyes locked on Luca’s; they were blue like Teel’s, but this was not Teel. Luca, panicking and revolted, thrashed until he had pushed her away.

But without the trooper on his back he was uncovered. Some instinct made him try to dig himself into the dirt. Perhaps he could hide there. But deeper than a hand’s breadth or so the dirt was compact, hardened by aeons, resistant to his scrabbling fingers.

A shadow moved across the light. Luca flinched and looked up. It was a ship, a vast graceful ship silhouetted against the light of battle.

The Xeelee nightfighter was a sycamore seed wrought in black a hundred metres across. The wings swept back from the central pod, flattening and thinning until at their trailing edges they were so fine Luca could see starbreaker fire through them. The Xeelee was swooping low over the asteroid’s surface - impossibly low, impossibly graceful, utterly inhuman. Threads of starbreaker light connected it to the ground, pulses of death dealt at the speed of light. Luca couldn’t tell if their source was the ship or the ground. Where the ship’s shadow passed explosions erupted from the asteroid’s surface, and bodies and bits of equipment were hurled up to go flying into space on neat straight-line trajectories.

Beneath the gaze of that dark bird, Luca felt utterly exposed.

There was a fresh crater not metres away, a scrap of shelter. He closed his eyes. ‘One, two, three.’ He pushed himself to hands and knees and tried a kind of low-gravity crawl, pulling at the surface with his hands and digging his toes into the dust, squirming over the ground like an insect.

He reached the crater and threw himself into it. But again the low gravity had fooled him, and he took an age to complete his fall.

The massive wing of the nightfighter passed over him. It was only metres above him; if he had jumped up he could have touched it. He felt a tugging, like a tide, passing along his body, and light flared all around him. He clamped his hands over his head and closed his eyes.

The cherry-red light faded, and that odd sensation of tugging passed. He risked looking up. The Xeelee had moved beyond him. It was tracking over the asteroid’s close horizon, setting like a great dark sun, and it dragged a webbing of red light beneath it as it passed.

There was a brief lull. The light of more distant engagements bathed the ground in a paler, more diffuse glow.

Something moved on the ground. It was a trooper, crawling out of a hole a little deeper than Luca’s. He, she, moved hunched over, looking only half human. One leg was dragging. Luca saw now that the trooper had lost a foot, cleanly scythed, and that the lower leg of the skinsuit was tied off by a crude tourniquet. More troopers came clambering out of holes and trenches, or even out of the cover of the bodies of their comrades. They crawled, walked, flopped back towards their trenches.

But the red light erupted again, raking flat across the curved landscape. The beams lanced through the bodies of the wounded as they tried to crawl, and they staggered and fell, cut open and sliced - or they simply exploded, the internal pressure of their bodies destroying them in silent, bloody bursts.

Still Luca was unharmed, as if this withering fire was programmed to avoid him. But, turned around and battered, he didn’t know where his trench was, where he should go. And dust was thrown up around him by silent detonations, obscuring his vision. He saw a brighter light ahead, a cool whiteness, as if seen through a fog of dust and frozen blood. He pulled himself out of the crater and crawled that way.

Again the fire briefly faded. There was no air to suspend the dust, and as soon as the firing ceased it fell quickly back to the ground, or dispersed into space. As the dust cleared the white light was revealed.

It was no human shelter but the Sugar Lump itself, looming towards the Rock.

The Xeelee emplacement, a huge projection of power, was a cube, shining white, that spun slowly about shifting axes: it was an artefact the size of a small planet, a box that could have contained Earth’s Moon. And it was beautiful, Luca thought, fascinated, like a toy, its faces glowing sheets of white, its edges and corners a geometrical ideal. But its faces were scarred and splashed with rock.

He saw this through a stream of rocks that soared through their complex orbits towards the Sugar Lump. They looked like gravel thrown against a glowing window. But these were asteroids, each like his own Rock, kilometres across or more.

Red light punched through his shoulder. He stared, uncomprehending, as blood founted in a pencil-thin spray, before his suit sealed itself over and the flow stopped. He was able to raise his arm, even flex his fingers, but he couldn’t feel the limb, as if he had been sleeping on it. He could sense the pain, though, working its way through his shocked nervous system.

An explosion erupted not metres away.

A wave of dirt and debris washed him onto his back. At last pain pulsed in his arm, needle-sharp. But the dust cleared quickly, the grains settling out on their millions of parabolas to the surface from which they had been hurled, and the open sky was revealed again.

A face of the Sugar Lump was over him, sliding by like a translucent lid across the world, the edges too remote to see. Asteroids slid past its surface, sparking with weapons’ fire. The plane face itself rippled, holes dilating open like stretching mouths, and more Xeelee ships poured out, nightfighters like darting birds whose wings opened tentatively.

But a new fire opened up from the Rock, a blistering hail of blue-white sparks that hosed into the surface of the Sugar Lump itself. This was fire from a monopole cannon, Luca knew, and those blue-white sparks were point defects in spacetime. The Xeelee craft emerging from the Sugar Lump tried to open their wings. But the blue sparks ripped into them. One nightfighter went spinning out of control, to plummet back into the face of the Sugar Lump.

These few seconds of closest approach were the crux of the engagement, its whole purpose. Monopoles, point defects, would rip a hole in a nightfighter wing, or a Sugar Lump face. But you had to get close enough to deliver them. And you had to hit the Xeelee craft when they were vulnerable, which meant the few seconds or minutes after the nightfighters had emerged from the Sugar Lump emplacements, when they were slow, sluggish, like baby birds emerging from a nest. That was why you had to get in so close to the Sugar Lump, despite the ferocious fire, and you had to use the precious seconds of closest approach as best you could - and then try to get out before the Xeelee assembled their overwhelmingly superior weaponry. That was why Luca was here; that was why so many were screaming and dying around him.

Luca felt hate well up inside him, hate for the Xeelee and what they had done to mankind, the deaths and pain they had inflicted, the massive distortion of human destiny. And as the human weapons ripped holes in the Xeelee emplacement he roared a visceral cry of loathing and triumph.

But now somebody stood over him, shadowed against the Sugar Lump face.

‘Bayla? Teel?’

A heavy hand reached down, grabbed a handful of his tunic, and hauled Luca up. He was carried across the surface, floppy-limbed, with remarkable speed and efficiency. The sky, still crowded with conflict, rocked above him.

He was hurled into a hole in the ground. He fell through low gravity and landed in darkness on a heap of bodies, a tangle of limbs. Med cloaks were wrapped around the injured, but many of the cloaks glowed bright blue, the colour of death, so that this chamber in the rock was filled with eerie electric-blue shadows.

More bodies poured in after Luca, tumbling on top of him. The mouth of the tunnel closed over, blocking out the light of battle. There was a second of stillness. Luca squirmed, trying to get out from under the heap of bodies.

Then the stomping began. It was exactly as if some immense boot was slamming down on the asteroid. The people in the chamber were thrown up, dropped back, shaken. Splinters of bright white light leaked into the tunnel through its layers of sealing dirt. Luca found himself rolling, kicked and punched. Ignoring the pain in his shoulder he fought with his fists and feet until he found himself huddled in a corner of wall and floor. He hugged his knees to his chest, making himself a small, hard boulder.

Still the slamming went on. He could feel it in his bones, his very flesh. He closed his eyes. He tried to think of the Conurbation where he had been born, and joined his first cadres. It had been an open place of parks and ruined Qax domes. In the mornings he would run and run, his cloak flapping around his legs, the dewy grass sharp under his bare feet. He had never been more alive - certainly more than now, sealed up in this suit in a hole in the shuddering ground.

He huddled over, dreaming of Earth. Perhaps if he dug deep down inside himself he would find a safe place to live, inside his memory, safe from this war. But still the great stamping went on and on, as he remembered the dew on the grass.

Luca. Novice Luca.

He had never understood.

Oh, logically he knew of the endless warfare at the heart of the Galaxy, the relentless deaths, the children thrown into the fire. But he had never understood it, on a deep, human level. So many human dead, he thought, buried in meaningless rocks like this or scattered across space, as if the disc of the Galaxy itself is rotten with our corpses. There they wait until the latest generation joins them, falling down like sparks into the dark.

Luca.

He tried to remember his ambitions, how he used to feel, when the war had been a fascinating exercise in logistics and ideology, a source of endless career opportunities for bright young Commissaries. How could he have been so dazzled by such fantasies?

It was as if a great crime was being committed, out of sight. Whether humans won this war or not, nothing would ever be the same - nothing ever could compensate for the relentless evil being committed here. We’re like those wretched children on New Earth forced to commit atrocities against those they love, he thought. We can’t go back. Not after what we have done here.

Luca. Luca. ‘. . . Luca. You are alive, like it or not. Look at me, Novice.’

Reluctantly, shedding the last of his cocoon of grass-green memory, he opened his eyes. He was still in the chamber of dirt. There was no light but the dimming glow of med cloaks. Nothing moved; everybody was still. But the stomping had stopped, he realised.

And here was Dolo’s Virtual head, a fuzzy ball of pixels, floating before him, glowing in the dark.

‘I’m in my grave,’ Luca said.

‘Less melodrama, please, Novice. The Navy knows you’re here. They’re on the way to dig you out.’

‘Teel—’

‘Is dead. So is Bayla, our anti-Doctrinal religionist.’ Dolo reeled off more names, everybody Luca could think of in the units he had met. ‘Everybody is dead, except you.’

Teel was dead. He tried to remember his feelings for Teel, that peculiar wistful love reciprocated by her on some level he had never understood. It had been everything in the world to him, he thought, just hours ago, and even after what he had seen of the child soldiers on New Earth and the rest, his head had been full of dreams of fighting alongside her - and, yes, of saving her from this place, just as she had understood. Now it all seemed remote, a memory of a memory, or the memory of a story told by somebody else.

As if they were back in the seminary, Dolo said, ‘Tell me what you are thinking. The surface of your mind.’

‘I have no sense of the true scale of this, the moral scale. I don’t even know what my own life is worth. I’m too small. I’ve nothing to measure it against.’

‘But it was that very scale that saved you. What defence do we have, we feeble humans, against the Xeelee?’

‘None.’

‘Wrong. Listen to me. We are fighting a war on an interstellar scale. The Xeelee push out of the Core; we push them back, endlessly. The Front is a vast belt of friction, right around the Galaxy’s centre, friction between huge wheels spun by the Xeelee and ourselves, rubbing away lives and material as fast as we can pour them in. It’s been this way, virtually static, for two thousand years.

‘But if you are caught in the middle of it, your defence is numbers. Your defence is statistical. If there are enough of you, even if others are taken, you might survive. We have probably been using such strategies all the way back to the days without fire or tools, on some treeless plain on Earth. When the predators come, let them take her - the slowest, the youngest or oldest, the weakest, the unlucky - but I will survive. Death is life, remember; that was what Teel said: the death of others is my life.’

Luca looked into Dolo’s eyes; the low-quality image had only empty, staring sockets. ‘It is a vermin’s strategy.’

‘We are vermin.’

‘Does the arch still stand?’

‘It is sited on the far side of the asteroid, away from the main weapons sites. Yes, it stands.’

‘Let it be,’ Luca said. ‘The religion. The worship of Poole at Timelike Infinity.’

Dolo’s head pushed closer. ‘Why?’

‘Because it gives the troopers a meaning the dry Doctrines can’t supply. A belief in a simple soldiers’ heaven makes no difference.’

‘But it does make a difference,’ Dolo said quietly. ‘Remember that we need to manage the historical stability of the Expansion. Far from being damaging, I now believe this proto-religion might actually be useful in ensuring that.’ He laughed. ‘We will probably support it, discreetly. Perhaps we will even write some scripture for it. We have before. In the end we don’t care what they think they are fighting for, as long as they fight.’

‘Why?’

‘Why what?’

‘Why do you do this? And—’

‘And why do I so obviously enjoy it? Ha!’ Dolo tipped back his Virtual face. ‘Because it is a kind of exploration, Novice. There will always be another battlefield - another star, even, one day, another Galaxy - and each is much like the last. But here we are exploring the depths of humanity itself. How far can a human being be degraded and brutalised before something folds up inside? I can tell you, we haven’t reached the bottom of that yet, and we’re still digging.

‘And then there is the war itself, the magnificence of the enterprise. Think about it: we are trying to build a perfect killing machine from soft human components, from swarming animals who evolved in a very different place, very far from here. It is a marvellous intellectual exercise - don’t you think?’

Luca dropped his face. He said, ‘How can we win this war?’

Dolo looked puzzled. ‘But we have no interest in mere winning, but in the perfecting of humanity. And to achieve that we need eternity, an eternal war. Victory is trivial compared to that.’

‘No,’ Luca said.

‘Novice—’

Dirt showered over him. Fragments rained through Dolo’s Virtual, making it flicker. Luca looked up. A machine had broken through the roof of the cavern, revealing the light of the Galaxy Core.

Skinsuited troopers clustered around the hole. One leapt down and just picked up Luca under his shoulders. Luca cried out at the pain of his wound, but he was hoisted up towards the sky and released.

For a second, two, he floated up through the vacuum, as if dreaming.

Then more strong hands caught him. He was wrapped in a med cloak. It snuggled around him and he immediately felt its warmth.

Everywhere he looked he saw more teams digging, and bodies floating out of the dirt. It was as if the whole Rock were a cemetery fifty kilometres across, disgorging its dead. And over his comms system he could hear a great murmuring groan. It was the merging of thousands of voices, he realised, the thousands of wounded that still littered this battered Rock, who themselves were far outnumbered by the dead.

‘No,’ he muttered.

A visored face loomed over him. ‘No what?’

‘We have to find a way to win this war,’ Luca whispered.

‘Sure we do. Save your strength, buddy.’ The med cloak probed at his shoulder. He felt a sharp pain.

And then sleep engulfed him, shutting out the light of the war.

The seed inadvertently planted by Dolo and others, in allowing the soldiers’ new religion to survive, took a long time to bear fruit.

In the meantime Luca was right. Humanity had to find a way to win its war before it lost through sheer exhaustion. It was through the slow sedition of Luca and others like him that the victory came about.

But it would take two more bloody millennia before the heroics of what became known as the ‘Exultant generation’ broke the logjam of the Front, and mankind’s forces swept on into the Core itself.

I had a small part to play in that victory. We undying, hidden away, have sometimes seen fit to steer human history. With patience you can make a difference. But mayflies, blind to the long term, are impossible to herd. You never get everything you want.

Still, a victory.

Suddenly the Galaxy was human.

Victorious child soldiers peered around at what they had won, uncomprehending, and wondered what to do next.

Mankind sought new purposes.

For the first time in many millennia voyages of discovery, not conquest, were launched. Some even sailed beyond the Galaxy itself.

And even there they found relics of mankind’s complicated history.

Some were almost as old as I am.

MAYFLOWER II

AD 5420-24,974

I

Twenty days before the end of his world, Rusel heard that he was to be saved.

‘Rusel. Rusel . . .’ The whispered voice was insistent. Rusel rolled over, trying to shake off the effects of his usual mild sedative. The room responded to his movement, and soft light coalesced around him. His pillow was soaked with sweat.

His brother’s face was hovering in the air at the side of his bed. Diluc was grinning. The Virtual image made his face look even wider than usual, his nose more prominent.

‘Lethe,’ Rusel said hoarsely. ‘You ugly bastard.’

‘You’re just jealous,’ Diluc said. ‘I’m sorry to wake you. But I just heard - you need to know—’

‘Know what?’

‘Blen showed up in the infirmary.’ Blen was the nanochemist assigned to Ship Three. ‘Get this: he has a heart murmur.’ Diluc’s grin returned.

Rusel frowned. ‘For that you woke me up? Poor Blen.’

‘It’s not that serious. But, Rus - it’s congenital.’

The sedative dulled Rusel’s thinking, and it took him a moment to figure it out.

The five Ships were to evacuate the last, brightest hopes of Port Sol from the path of the incoming peril, the forces of the young Coalition. But they were slower-than-light transports, and would take many centuries to reach their destinations. Only the healthiest, in body and genome, could be allowed aboard a generation starship. And if Blen had a hereditary heart condition—

‘He’s off the Ship,’ Rusel breathed.

‘And that means you’re aboard, brother. You’re the second-best nanochemist on this lump of ice. You won’t be here when the Coalition arrives. You’re going to live!’

Rusel lay back on his crushed pillow. He felt numb.

His brother kept talking. ‘Did you know that families are illegal under the Coalition? Their citizens are born in tanks. Just the fact of our relationship would doom us, Rus! I’m trying to fix a transfer from Five to Three. If we’re together, that’s something, isn’t it? I know it’s going to be hard, Rus. But we can help each other. We can get through this . . .’

All Rusel could think about was Lora, whom he would have to leave behind.

The next morning Rusel arranged to meet Lora in the Forest of Ancestors. He took a bubble-wheel surface transport, and set out early.

Port Sol was a planetesimal, an unfinished remnant of the formation of Sol system. Inhabited for millennia, its surface was heavily worked, quarried and pitted, and littered by abandoned towns. The Qax had never come here; Port Sol was a museum, some said, of pre-Occupation days. But throughout Port Sol’s long human usage some areas had been kept pristine, and as he drove Rusel kept to the marked track, to avoid crushing the delicate sculptures of frost that had coalesced here over four billion years.

And visible beyond the close horizon of the ice moon was a squat cylinder, a misty sketch in the faint sunlight. That was Ship Three, preparing for its leap into the greater dark.

This was the very edge of Sol system. The sky was a dome of stars, with the ragged glow of the Galaxy hurled casually across its equator. Set in that diffuse glow was the sun, the brightest star, bright enough to cast shadows, but so remote it was a mere pinpoint. Around the sun Rusel could make out a tiny puddle of light: the inner system, the disc of worlds, moons, asteroids, dust and other debris that had been the arena of all human history before the first interplanetary voyages some three thousand years earlier, and still the home of all but an invisible fraction of the human race. This was a time of turmoil, and today, invisible in that pale glow, humans were fighting and dying. And even now a punitive fleet was ploughing out of that warm centre, heading for Port Sol.

The whole situation was an unwelcome consequence of the liberation of Earth from the alien Qax, just thirteen years earlier. The Interim Coalition of Governance, the new, ideologically pure and viciously determined central authority that had emerged from the chaos of a newly freed Earth, was already burning its way out through the worlds and moons of Sol system. When the Coalition ships came, the best you could hope for was that your community would be broken up, your equipment impounded, and that you would be hauled back to a prison camp on Earth or its Moon for ‘reconditioning’.

But if a world was found to be harbouring anyone who had collaborated with the hated Qax, the penalties against it were much more extreme. The word Rusel had heard was ‘resurfacing’.

Now the Coalition had turned its attention to Port Sol. This ice moon was governed by five ‘pharaohs’, as they were called locally, an elite group who had indeed collaborated with the Qax - though they described it as ‘mediating the effects of the Occupation for the benefit of mankind’ - and they had received anti-ageing treatments as a reward. So Port Sol was a ‘nest of illegal immortals and collaborators’, the Coalition said, and dispatched its troops to ‘clean it out’. It seemed indifferent to the fact that, in addition to the pharaohs, some fifty thousand people called Port Sol home.

The pharaohs had a deep network of spies on Earth, and they had had some warning of the coming of the Coalition. As the colonists had only the lightest battery of antiquated weaponry - indeed the whole ice moon, a refuge from the Occupation, was somewhat low-tech - nobody expected to be able to resist. But there was a way out.

Five huge Ships were hastily thrown together. On each Ship, captained by a pharaoh, a couple of hundred people, selected for their health and skill sets, would be taken away: a total of a thousand, perhaps, out of a population of fifty thousand, saved from the incoming disaster. There was no faster-than-light technology on Port Sol; these would be generation starships. But perhaps that was as well. Between the stars there would be room to hide.

All these mighty historical forces had now focused down on Rusel’s life, and they threatened to tear him away from his lover.

Lora was waiting for him at the Forest of Ancestors. They met on the surface, embracing stiffly through their skinsuits. Then they set up a dome-tent and crawled through its collapsible airlock.

In the Forest’s long shadows, Rusel and Lora made love: at first urgently, and then again, more slowly, thoughtfully. In the habs, inertial generators kept the gravity at one-sixth standard, about the same as Earth’s Moon. But there was no gravity control out here in the Forest, and as they clung to each other they drifted in the tent’s cool air, light as dreams.

Rusel told Lora his news.

Rusel was an able nanochemist, he was the right age for Ship crew, and his health and pedigree were immaculate. But unlike his brother he hadn’t been good enough to win the one-in-fifty lottery and make the cut to get a place on the Ships. He was twenty-eight years old: not a good age to die. But he had accepted his fate, so he believed - for Lora, his lover, had no hope of a berth. At twenty she was a student, a promising Virtual idealist but without the mature skills to have a chance of competing for a berth on the Ships. So at least he would be with her, when the sky fell in.

He was honest with himself, and unsentimental; he had never been sure if his noble serenity would have survived the appearance of the Coalition ships in Port Sol’s dark sky. And now, it seemed, he was never going to find out.

Lora was slim, delicate. The population of this low-gravity moon tended to tallness and thin bones, but Lora seemed to him more elfin than most, and she had large, dark eyes that always seemed a little unfocused, as if her attention was somewhere else. It was that sense of other-world fragility that had first attracted Rusel to her.

With blankets bundled over her legs, she took his hand and smiled. ‘Don’t be afraid.’

‘I’m the one who’s going to live. Why should I be afraid?’

‘You’d accepted dying. Now you’ve got to get used to the idea of living.’ She sighed. ‘It’s just as hard.’

‘And living without you.’ He squeezed her hand. ‘Maybe that’s what scares me most. I’m frightened of losing you.’

‘I’m not going anywhere.’

He gazed out at the silent, watchful shapes of the Ancestors. These ‘trees’, some three or four metres high, were stumps with ‘roots’ that dug into the icy ground. They were living things, the most advanced members of Port Sol’s low-temperature aboriginal ecology. This was their sessile stage. In their youth, these creatures, called ‘Toolmakers’, were mobile, and were actually intelligent. They would haul themselves across Port Sol’s broken ground, seeking a suitable crater slope or ridge face. There they would set down their roots and allow their nervous systems and their minds to dissolve, their purposes fulfilled.

Rusel wondered what liquid-helium dreams might be coursing slowly through the Ancestors’ residual minds. They were beyond decisions now; in a way he envied them.

‘Maybe the Coalition will spare the Ancestors.’

She snorted. ‘I doubt it. The Coalition only care about humans - and their sort of humans at that.’

‘My family has lived here a long time,’ he said. ‘There’s a story that says we rode out with the first colonising wave.’ It was a legendary time, when the engineer Michael Poole had come barnstorming all the way through the system to Port Sol to build his great starships.

She smiled. ‘Most families have stories like that. After thousands of years, who can tell?’

‘This is my home,’ he blurted. ‘This isn’t just the destruction of us, but of our culture, our heritage. Everything we’ve worked for.’

‘But that’s why you’re so important.’ She sat up, letting the blanket fall away, and wrapped her arms around his neck. In Sol’s dim light her eyes were pools of liquid darkness. ‘You’re the future. The pharaohs say that in the long run the Coalition will be the death of mankind, not just of us. Somebody has to save our knowledge, our values, for the future.’

‘But you—’ You will be alone, when the Coalition ships descend. Decision sparked. ‘I’m not going anywhere.’

She pulled back. ‘What?’

‘I’ve decided. I’ll tell Pharaoh Andres, and my brother. I can’t leave here, not without you.’

‘You must,’ she said firmly. ‘You’re the best for the job, believe me; if not the pharaohs wouldn’t have selected you. So you have to go. It’s your duty.’

‘What human being would run out on those he loved?’

Her face was set, and she sounded much older than her twenty years. ‘It would be easier to die. But you must live, live on and on, live on like a machine, until the job is done, and the race is saved.’

Before her he felt weak, immature. He clung to her, burying his face in the soft warmth of her neck.

Nineteen days, he thought. We still have nineteen days. He determined to cherish every minute.

But as it turned out they had much less time than that.

Once again he was woken in the dark. But this time his room lights were snapped full on, dazzling him. And it was the face of Pharaoh Andres that hovered in the air beside his bed. He sat up, baffled, his system heavy with sedative.

‘—thirty minutes. You have thirty minutes to get to Ship Three. Wear your skinsuit. Bring nothing else. If you aren’t there in thirty minutes, twenty-nine forty-five, we leave without you.’

At first he couldn’t take in what she said. He found himself staring at her face. Her head was hairless, her scalp bald, her eyebrows and even her eyelashes gone. Her skin was oddly smooth, her features small; she didn’t look young, but as if her face had sublimated with time, like Port Sol’s ice landscapes, leaving this palimpsest. She was rumoured to be two hundred years old.

‘Don’t acknowledge this message, just move. We lift in twenty-nine minutes. If you are Ship Three crew, you have twenty-nine minutes to get to—’

She had made a mistake: that was his first thought. Had she forgotten that there were still sixteen days to go before the Coalition ships were due? But he could see from her face there was no mistake.

Twenty-nine minutes. He reached down to his bedside cabinet, pulled out a nano pill and gulped it down dry. Reality bleached, becoming cold and stark.

He dragged on his skinsuit and sealed it roughly. He glanced around his room, at his bed, his few pieces of furniture, the Virtual unit on the dresser with its images of Lora. Bring nothing. Andres wasn’t a woman you disobeyed in the slightest particular.

Without looking back he left the room.

The corridor outside was bedlam. A thousand people shared this under-the-ice habitat, and all of them seemed to be out tonight. They ran this way and that, many in skinsuits, some hauling bundles of gear. He pushed his way through the throng. The sense of panic was tangible - and, carried on the recycled air, he thought he could smell burning.

His heart sank. It was obviously a scramble to escape - but the only way off the moon was the Ships, which could take no more than a thousand. Had the sudden curtailing of the time left triggered this panic? In this ultimate emergency had the citizens of Port Sol lost all their values, all their sense of community? What could they hope to achieve by hurling themselves at Ships that had no room for them, but to bring everybody down with them? But what would I do? He could afford the luxury of nobility; he was getting out of here.

Twenty minutes.

He reached the perimeter concourse. Here, surface transports nuzzled against a row of simple airlocks. Some of the locks were already open, and people were crowding in, pushing children, bundles of luggage. His own car was still here, he saw with relief. He pulled open his skinsuit glove and hastily pressed his palm to the wall. The door hissed open.

But before he could pass through, somebody grabbed his arm.

A man faced him, a stranger, short, burly, aged perhaps forty. Behind him a woman clutched a small child and an infant. The adults had blanket-wrapped bundles on their backs. The man wore an electric-blue skinsuit, but his family were in hab clothes.

The man said desperately, ‘Friend, you have room in that thing?’

‘No,’ Rusel said.

The man’s eyes hardened. ‘Listen. The pharaohs’ spies got it wrong. Suddenly the Coalition is only seven days out. Look, friend, you can see how I’m fixed. The Coalition breaks up families, doesn’t it? All I’m asking is for a chance on the Ships.’

‘But there won’t be room for you. Don’t you understand? And even if there were—’ There were to be no children on the Ships at launch: that was the pharaohs’ harsh rule. In the first years of the long voyage, everybody aboard had to be maximally productive. The time for breeding would come later.

The man’s fist bunched. ‘Listen, friend—’

Rusel shoved the man in the chest. He fell backwards, stumbling against his children. His blanket bundle broke open, and goods spilled on the floor: clothes, diapers, children’s toys.

‘Please.’ The woman approached him, stepping over her husband. She held out a baby. ‘Don’t let the Coalition take him away. Please.’

The baby was warm, soft, smiling. Rusel automatically reached out. But he stopped himself cold, and turned away.

He pushed into his car, slammed shut the door, and stabbed a preset routine into the control panel. The woman with the baby continued to call after him. How could I do that? I’m no longer human, he thought.

The car ripped itself away from the airlock interface, ignoring all safety protocols, and began to haul itself on its bubble wheels up the ramp from the under-the-ice habitat to the surface. Shaking, Rusel opened his visor. He might be able to see the doomed family at the airlock port. He didn’t look back.

It wasn’t supposed to be like this.

Andres’s Virtual head coalesced before him. ‘Sixteen minutes to get to Ship Three. If you’re not there we go without you. Fifteen forty-five. Fifteen forty . . .’

The surface was almost as chaotic as the corridors of the hab, as transports of all types and ages rolled, crawled or jumped. There was no sign of the Enforcers, the pharaohs’ police force, and he was apprehensive about being held up in the crush.

He made it through the crowd and headed for the track that would lead through the Forest of Ancestors to Ship Three. Out here there was a lot of traffic, but it was more or less orderly, everyone heading out the way he was. He pushed the car up to its safety-regulated maximum speed. Even so, he was continually overtaken. Anxiety tore at his stomach.

The Forest, with the placid profiles of the Ancestors glimmering in Sol’s low light, looked unchanged from when he had last seen it, only days ago, on his way to meet Lora. He felt an unreasonable resentment that he had suddenly lost so much time, that his careful plan for an extended farewell to Lora had been torn up. He wondered where she was now. Perhaps he could call her.

Thirteen minutes. No time, no time.

The traffic ahead was slowing. The vehicles at the back of the queue weaved, trying to find gaps, and bunched into a solid pack.

Rusel punched his control panel and brought up a Virtual overhead image. Ahead of the tangle of vehicles, a ditch had been cut roughly across the road. People swarmed, hundreds of them. Roadblock.

Eleven minutes. For a moment his brain seemed as frozen as Port Sol ice; frantic, bewildered, filled with guilt, he couldn’t think.

Then a heavy-duty long-distance truck broke out of the pack behind him. Veering off the road to the left, it began to smash its way through the Forest. The elegant eightfold forms of the Ancestors were nothing but ice sculptures, and they shattered before the truck’s momentum. It was ugly, and Rusel knew that each impact wiped out a life that might have lasted centuries more. But the truck was clearing a path.

Rusel hauled at his controls, and dragged his car off the road. Only a few vehicles were ahead of him in the truck’s destructive wake. The truck was moving fast, and he was able to push his speed higher.

They were already approaching the roadblock, he saw. A few suit lights moved off the road and into the Forest, to stand in the path of the lead truck; the blockers must be enraged to see their targets evade them so easily. Rusel kept his speed high. Only a few more seconds and he would be past the worst.

But there was a figure standing directly in front of him, helmet lamp bright, dressed in an electric-blue skinsuit, arms raised. As the car’s sensors picked up the figure, its safety routines cut in, and he felt it hesitate. He slammed his palm to the control panel, overriding the safeties. Nine minutes.

He closed his eyes as the car hit the protester.

He remembered the blue skinsuit. He had just mown down the man from the airlock, who had been so desperate to save his family. He had no right to criticise the courage or the morals or the loyalty of others, he saw.

We are all just animals, fighting to survive. My berth on Ship Three doesn’t make me any better. He hadn’t even had the guts to watch.

Eight minutes. He disabled the safety governors and let the car race down the empty road, its speed ever increasing.

He had to pass through another block before he reached Ship Three - but this one was manned by Enforcers. They were in an orderly line across the road, dressed in their bright yellow skinsuit uniforms. Evidently they had pulled back to tight perimeters around the five Ships. At least they were still loyal.

The queuing was agonising. With only five minutes before Andres’s deadline, an Enforcer pressed a nozzle to the car’s window, flashed laser light into Rusel’s face, and waved him through.

Ship Three was directly ahead of him. It was a drum, a squat cylinder about a kilometre across and half as tall. It sat at the bottom of its own crater, for Port Sol ice had been gouged out and plastered roughly over the surface of its hull. It looked less like a ship than a building, he thought, a building coated by thick ice, as if long abandoned. But it was indeed a starship, a ship designed for a journey of not less than centuries, and fountains of crystals already sparkled around its base in neat parabolic arcs: steam from the Ship’s rockets, freezing immediately to ice. People milled at its base, running clumsily in the low gravity, and scurried up ramps that tongued down from its hull to the ground.

Rusel abandoned the car, tumbled out onto the ice and ran towards the nearest ramp. There was another stomach-churning wait as an Enforcer in glowing yellow checked each identity. At last, after another dazzling flash of laser light in his eyes, he was through.

He hurried into an airlock. As it cycled it struck him that as he boarded this Ship, he was never going to leave it again: whatever became of him, this Ship was his whole world, for the rest of his life.

The lock opened. He ripped off his helmet. The light was emergency red, and klaxons sounded throughout the ship; the air was cold, and smelled of fear. Lethe, he was aboard! But there could only be a minute left.

He ran along a cold, ice-lined corridor towards a brighter interior.

He reached an amphitheatre, roughly circular, carpeted by acceleration couches. Andres’s voice boomed from the air: ‘Get into a couch. Any couch. It doesn’t matter. Forty seconds. Strap yourself in. Nobody is going to do it for you. Your safety is your own responsibility. Twenty-five seconds.’ People swarmed, looking for spare couches. The scene seemed absurd to Rusel, like a children’s game.

‘Rus! Rusel!’ Through the throng, Rusel made out a waving hand. It was Diluc, his brother, wearing his characteristic orange skinsuit. ‘Lethe, I’m glad to see you. I kept you a couch. Come on!’

Rusel pushed that way. Ten seconds. He threw himself down on the couch. The straps were awkward to pull around the bulk of his suit.

As he fumbled, he stared up at a Virtual display that hovered over his head. It was a view as seen from the Ship’s blunt prow, looking down. Those tongue ramps were still in place, radiating down to the ice. But now a dark mass boiled around the base of the curving hull: people, on foot and in vehicles, a mob of them closing in. In amongst the mass were specks of bright yellow. Some of the Enforcers had turned on their commanders, then. But others stood firm, and in that last second Rusel saw the bright sparks of weapon fire, all around the base of the Ship.

A sheet of brilliant white gushed out from the Ship’s base. It was Port Sol ice, superheated to steam at tens of thousands of degrees. The image shuddered, and Rusel felt a quivering, deep in his gut. The Ship was rising, right on time, its tremendous mass raised on a bank of rockets.

When that great splash of steam cleared, Rusel saw small dark forms lying motionless on the ice: the bodies of the loyal and disloyal alike, their lives ended in a fraction of a second. A massive shame descended on Rusel, a synthesis of all the emotions that had churned through him since that fateful call of Diluc’s. He had abandoned his lover to die; he had probably killed others himself; and now he sat here in safety as others died on the ice below. What human being would behave that way? He felt the shame would never lift, never leave him.

Already the plain of ice was receding, and weight began to push at his chest.

II

Soon Port Sol fell away, and even the other Ships were lost against the stars, and it was as if Ship Three was alone in the universe.

In this opening phase of its millennial voyage Ship Three was nothing more than a water rocket, as its engines steadily sublimated its plating of ice and hurled steam out of immense nozzles. But those engines drew on energies that had once powered the expansion of the universe itself. Later the Ship would spin up for artificial gravity and switch to an exotic ramjet for its propulsion, and its true journey would begin.

The heaviest acceleration of the whole voyage had come in the first hours, as the ship hurled itself away from Port Sol. After that the acceleration was cut to about a third standard - twice lunar gravity, twice what the colonists of Port Sol had been used to. For the time being, the acceleration couches were left in place in that big base amphitheatre, and in the night watches everybody slept there, all two hundred of them massed together in a single vast dormitory, their muscles groaning against the ache of the twice-normal gravity.

The plan was that for twenty-one days the Ships would actually head towards the sun. They would penetrate Sol system as far as the orbit of Jupiter, where they would use the giant planet’s gravity field to slingshot them on to their final destinations. It seemed paradoxical to begin the exodus by hurling oneself deep into the inner system, the Coalition’s home territory. But space was big, the Ships’ courses had been plotted to avoid the likely trajectory of the incoming Coalition convoy, and the Ships were to run silently, not even communicating with each other. The chances of them being detected were negligible.

Despite the wearying gravity the first days after launch were busy for everybody. The Ship’s interior had to be rebuilt from its launch configuration to withstand this high-acceleration cruise phase. And the daily routines of the long voyage had to be set up - the most important of them being cleaning.

The Ship was a closed environment and its interior had plenty of smooth surfaces where biofilms, slick detergent-proof cities of bugs, would quickly build up. Not only that, the fall-out of the Ship’s human cargo - flakes of skin, hair, mucus - were seed beds for bacterial growth. All of this had to be eliminated; Captain Andres declared she wanted the Ship to be as clean as a hospital.

The most effective way to achieve that - and the most ‘future-proof’, in Andres’s persistent jargon - was through the old-fashioned application of human muscle. Everybody had to pitch in, even the Captain herself. Rusel put in his statutory half-hour per day, scrubbing vigorously at the walls and floors and ceilings around the nanofood banks that were his primary responsibility. He welcomed the mindlessness of the work; he continued to seek ways in which to distract himself from the burden of thought.

He was briefly ill. In the first couple of weeks, everybody caught colds from everybody else. But the viruses quickly ran their course through the Ship’s small population, and Rusel felt obscurely reassured that he would likely never catch another cold in his life.

A few days after launch Diluc came to find him. Rusel was up to his elbows in slurry, trying to find a fault in a nanofood bank’s waste vent. Working non-stop, Rusel had seen little of his brother. He was surprised by how cheerful Diluc appeared, and how energetically he threw himself into his own work on the air cycling systems. He spoke brightly of his ‘babies’, fans and pumps, humidifiers and dehumidifiers, filters and scrubbers and oxygenators.

In their reaction to the sudden severance of the launch, the crew seemed to be dividing into two rough camps, Rusel thought. There were those like Diluc who were behaving as if the outside universe didn’t exist; they were bright, brash, too loud, their laughter forced. The other camp, to which Rusel felt he belonged, retreated the other way, into an inner darkness, full of complicated shadows.

But today Diluc’s mood seemed complex. ‘Brother, have you been counting the days?’

‘Since launch? No.’ He hadn’t wanted to think about it.

‘It’s day seven. There’s a place to watch. One of the observation lounges. Captain Andres says it’s not compulsory, but if . . .’

It took Rusel a moment to think that through. Day seven: the day the Coalition convoy was due to reach Port Sol. Rusel flinched from the thought. But one of his worst moments of that chaotic launch day was when he had run down that desperate father and driven on, without even having the courage to watch what he was doing. Perhaps this would atone. ‘Let’s do it,’ he said.

Ship Three, like its four siblings, was a fat torus. To reach the observation lounge the brothers had to ride elevators up through several decks to a point in the Ship’s flattened prow, close to the rim. The lounge, crammed with Virtual generation gear, was already configured for the spin-up phase to come, and most of its furniture was plastered to the walls, which would become the floor. It was big enough for maybe fifty people, and it was nearly full; Rusel and Diluc had to crowd in. Pharaoh Andres - now Captain Andres, Rusel reminded himself - was here, sitting in a deep, heavy-looking chair, front and centre before an immense, shining Virtual.

A ball of ice spun grandly before their eyes. It was Port Sol, of course; Rusel immediately recognised its icy geography of ancient craters, overlaid by a human patterning of quarries and mines, habitats and townships, landing ports. In the inhabited buildings lights shone, defiantly bright in outer-system gloom. It was a sculpture in white and silver, and it showed no sign of the chaotic panic that must be churning in its corridors.

The sight took Rusel’s breath away. Somewhere down there was Lora; it was an almost unbearable thought, and he wished with all his heart he had stayed with her.

The Coalition convoy closed in.

Its ships materialised from the edge of the three-dimensional image, as if sliding in from another reality. The fleet was dominated by five, six, seven Spline warships. Confiscated from the expelled Qax, they were living ships each a kilometre or more wide, their hulls studded with weapons and sensors and crudely scrawled with the green tetrahedron that was the sigil of liberated humanity.

Rusel’s stomach filled with dread. ‘It’s a heavy force,’ he said.

‘They’ve come for the pharaohs,’ Diluc said grimly. ‘The Coalition is showing its power. Images like this are no doubt being beamed throughout the system.’

Then it began. The first touch of the energy beams, cherry-red, was almost gentle, and Port Sol ice exploded into cascades of glittering shards that drifted back to the surface, or escaped into space. Then more beams ploughed up the ice, and structures began to implode, melting, or to fly apart. A spreading cloud of crystals began to swathe Port Sol in a temporary, pearly atmosphere. It was silent, almost beautiful, too large-scale to make out individual deaths, a choreography of energy and destruction.

‘We’ll get through this,’ Diluc muttered. ‘We’ll get through this.’

Rusel felt numbed, no grief, only shame at his own emotional inadequacy. This was the destruction of his home, of a world, and it was beyond his imagination. Worse, Port Sol, which had survived the alien occupation of the solar system, was being devastated by humans. How could such things happen? He tried to focus on one person, on Lora, to imagine what she must be doing if she was still alive: perhaps fleeing through collapsing tunnels, or crowding into deep shelters. But, in the ticking calm of this lounge, with its fresh smell of new equipment, he couldn’t even picture that.

As the assault continued, numbers flickered across the status display, an almost blasphemous tallying of the estimated dead.

Even after the trauma of Port Sol, work had to continue on booting up the vital systems that would keep them all alive.

Rusel’s own job, as the senior nanochemist on the Ship, was to set up the nanofood banks that would play a crucial part in recycling waste into food and other consumables like clothing. The work was demanding from the start. The banks were based on an alien technology, nano-devices purloined from the occupying Qax; only partially understood, they were temperamental and difficult.

It didn’t help that of the two assistants he had been promised a share of - most people were generalists in this small, skill-starved new community - only one had made it onto the Ship. It turned out that in the final scramble about ten per cent of the crew had been left behind; conversely, about ten per cent of those who actually were aboard shouldn’t have been here at all. A few shame-faced ‘passengers’ were yellow-uniformed Enforcers who in the last moments had abandoned their posts and fled to the sanctuary of the Ship’s interior.

The work had to get done anyhow. And it was urgent; until the nanofood was available the Ship’s temporary rations were steadily depleting. The pressure on Rusel was intense. But Rusel was glad of the work, so hard mentally and physically in the high gravity he had no time to think, and when he hit his couch at night he slept easily.

On the fifteenth day Rusel achieved a small personal triumph as the first slab of edible food rolled out of his nano-banks. Captain Andres had a policy of celebrating small achievements, and she was here as Rusel ceremoniously swallowed the first mouthful of his food, and she took the second. There was much clapping and back-slapping. Diluc grinned in his usual huge way. But Rusel, numbed inside, didn’t feel much like celebrating. People understood; half the crew, it was estimated, were still in some kind of shock. He got away from the crush as quickly as he could.

On the twenty-first day the Ship was to encounter Jupiter.

Captain Andres called the crew together in the acceleration-couch amphitheatre, all two hundred of them, and she set up a Virtual display in the air above them. Few of the crew had travelled away from Port Sol before; they craned to see. The sun was just a pinpoint, though much brighter than seen from Port Sol, and Jupiter was a flattened ball of cloud, racked with storm systems like bruises - the result, it was said, of an ancient battle.

The most intriguing sight of all was four sparks of light that slid across the background of stars. They were the other Ships, numbers One, Two, Four and Five; the little fleet would come together at Jupiter for the first time since leaving Port Sol, and the last.

Andres walked though the crowd on their couches, declaiming loudly enough for all to hear, her authority easy and unforced. ‘We pharaohs have been discussing destinations,’ she said. ‘Obviously the targets had to be chosen before we reached Jupiter; we needed to plan for our angles of emergence from Jupiter’s gravity well. The Coalition is vindictive and determined, and it has faster-than-light ships. It will soon overtake us - but space is big, and five silent-running generation starships will be hard to spot. Even so it’s obviously best to separate, to give them five targets to chase, not just one.

‘So we have five destinations. And ours,’ she said, smiling, ‘is the most unique of all.’

She listed the other Ships’ targets, star systems scattered through the disc of the Galaxy - none closer than five hundred light years. ‘All well within the Ships’ design parameters,’ she said, ‘and perhaps far enough to be safe. But we are going further.’

She overlaid the image of the shining Ships with a ruddy, shapeless mass of mist. ‘This is the Canis Major Dwarf Galaxy,’ she said. ‘Twenty-four thousand light years from Sol. It is the closest of the satellite galaxies - but it is beyond the main Galaxy itself, surely far outside the Coalition’s grasp for the foreseeable future.’

Rusel heard gasps throughout the amphitheatre. To sail beyond the Galaxy? . . .

Andres held her hands up to quell the muttering. ‘Of course such a journey is far in excess of what we planned. No generation starship has ever challenged such distances before, let alone achieved them.’ She stared around at them, fists on hips. ‘But if we can manage a thousand years of flight, we can manage ten, or fifty - why not? We are strong, we are just as determined as the Coalition and its drones - more so, for we know we are in the right.’

Rusel wasn’t used to questioning the pharaohs’ decisions, but he found himself wondering at the arrogance of the handful of pharaohs to make such decisions on behalf of their crew - not to mention the generations yet unborn.

There was no serious protest. Perhaps it was all simply beyond the imagination. Diluc muttered, ‘Can’t say it makes much difference. A thousand years or ten thousand, I’ll be dead in a century, and I won’t see the end . . .’

Andres restored the images of the Ships. Jupiter was expanding rapidly now, and the other Ships were swarming closer.

Andres said, ‘We have discussed names for our vessels. On such an epic voyage numbers won’t do. Every Ship must have a name! We have named our Ship-homes for great thinkers, and great vessels of the past.’ She stabbed her finger around the Virtual image. ‘Tsiolkovsky. Great Northern. Aldiss. Vanguard.’ She looked at her crew. ‘And as for us, only one name is possible. Like an earlier band of pilgrims, we are fleeing intolerance and tyranny; we sail into the dark and the unknown, carrying the hopes of an age. We are Mayflower.’

You didn’t study history on Port Sol. Nobody knew what she was talking about.

At the moment of closest approach Jupiter’s golden-brown cloudscape bellied over the upturned faces of the watching crew, and the Ships poured through Jupiter’s gravity well. Even now the rule of silence wasn’t violated, and the five Ships parted without so much as a farewell message.

From now on, wherever this invisible road in the sky took her, the second Mayflower was alone.

III

As the days stretched to weeks, and the weeks to months, Rusel continued to throw himself into work - and there was plenty of it for everybody.

The challenges of running a generation starship were familiar to the crew to some extent, as the colonists of Port Sol had long experience in ecosynthesis, in constructing and sustaining closed artificial environments. But on Port Sol they had had external resources to draw on, the ice, rock and organic chemistry of the ice moon itself. The Ship was now cut off from the outside universe.

So the cycles of air, water and solids would have to be maintained with something close to a hundred per cent efficiency. The sealing of the Ship against leakages was vital, and so nano-machines laboured to knit together the hull. The control of trace contaminants and pests would have to be ferociously tight: more swarms of nano-bots were sent scurrying in pursuit of flakes of hair and skin.

Not only that, the Ship’s design had been hastily thrown together, and the vessel wasn’t even completed on launch. The construction had been a hurried project anyhow, and the shaving-off of those final ten or twelve days of preparation time, as the Coalition fleet sneaked up in the dark, had made a significant difference. So the crew laboured to complete the ship’s systems in flight.

The most significant difficulty, Rusel believed, was the sudden upping of the design targets. A thousand-year cruise, the nominal design envelope, was one thing. Now it was estimated that, cruising at about half lightspeed, it would take Ship Three fifty times as long to reach Canis Major. Even relativistic time dilation would only make a difference of a few per cent to the subjective duration. As a consequence the tolerances on the Ship’s systems were tightened by orders of magnitude.

There was yet another goal in all this rebuilding. A key lesson of ecosynthesis was that the smaller the biosphere, the more conscious control it would require. The Ship was a much smaller environment than a Port Sol habitat, and that presented problems of stability; the ecological system was poorly buffered and would always be prone to collapse. It was clear that this small, tight biosphere would always have to be consciously managed if it were to survive.

That was manageable as long as the first crew, educated on Port Sol, were in command. But to ensure this in the long term the Ship’s essential systems were to be simplified and automated as far as possible, to reduce the skill level required to maintain them. They couldn’t foresee all that might befall the Ship, and so they were trying to ‘future-proof’ the project, in Andres’s jargon: to reduce the crew to the status of non-productive payload.

As Diluc put it with grim humour, ‘We can’t allow civilisation to fall in here.’

Despite the horror of Port Sol, the hard work, and the daunting timescale Andres had set - which Rusel suspected nobody believed anyhow - the rhythms of human life continued.

Diluc found a new partner, a plump, cheerful woman of about thirty called Tila. Diluc and Tila had both left lovers behind on Port Sol, and Tila had been forced to give up a child. Now they seemed to be finding comfort with each other. Diluc was somewhat put out when they were both hauled into Andres’s small private office to be quizzed about their relationship, but Andres, after much consulting of genetic maps, approved their continuing liaison.

Rusel was pleased for his brother, but he found Tila a puzzle. Most of the selected crew had been without offspring, back on Port Sol; few people with children, knowing they would have to leave them behind, had even offered themselves for selection. But Tila had abandoned a child. He saw no sign of this loss in her face, her manner; perhaps her new relationship with Diluc, and even the prospect of more children with him in the future, was enough to comfort her. He wondered what was going on inside her head, though.

As for Rusel, his social contacts were restricted to work. He found himself being subtly favoured by Captain Andres, along with a number of others of the Ship’s senior technicians. There was no formal hierarchy on the Ship - no command structure below Andres herself. But this group of a dozen or so, a meritocracy selected purely by proven achievement, began to coalesce into a kind of governing council of the Ship.

That was about as much social life as Rusel wanted. Otherwise he just worked himself to the point of exhaustion, and slept. The complex mass of emotions lodged inside him - agony over the loss of Lora, the shock of seeing his home destroyed, the shame of living on - showed no signs of breaking up. None of this affected his contributions to the Ship, he believed. He was split in two, split between inside and out, and he doubted he would ever heal. In fact he didn’t really want to heal. One day he would die, as so many others had, as Lora probably had; one day he would atone for his sin of survival in death.

Meanwhile there was always the Ship. He slowly widened the scope of his work, and began to develop a feel for the Ship as a whole. As the systems embedded, it was as if the Ship was slowly coming alive, and he learned to listen to the rhythm of its pumps, feel the sighing of its circulating air.

Though Andres continued to use the fanciful name she had given it, Rusel and everybody else thought of it as they always had: as Ship Three - or, increasingly, just the Ship.

Almost a year after Jupiter, Andres called her ‘council’ of twelve together in the amphitheatre at the base of the Ship. This big chamber had been stripped of its acceleration couches, and the dozen or so of them sat on temporary chairs in the middle of an empty grey-white floor.

Andres told them she wanted to discuss a little anthropology.

In her characteristic manner she marched around the room, looming over her crew. ‘We’ve had a good year, for which I thank you. Our work on the Ship isn’t completed - in a sense it never will be completed - but I’m now satisfied that Mayflower will survive the voyage. If we fail in our mission, it won’t be the technology that betrays us, but the people. And that’s what we’ve got to start thinking about now.’

Mayflower was a generation starship, she said. By now mankind had millennia of experience of launching such ships. ‘And as far as we know, every last one of them has failed. And why? Because of the people.

‘The most basic factor is population control. You’d think that would be simple enough! The Ship is an environment of a fixed size. As long as every parent sires one kid, on average, the population ought to stay stable. But by far the most common causes of mission loss are population crashes, in which the number of crew falls below the level of a viable gene pool and then shuffles off to extinction - or, more spectacularly, explosions in which too many people eat their way to the hull of their ship and then destroy each other in the resulting wars.’

Diluc said dryly, ‘Maybe that proves it’s just a dumb idea. The scale of the journey is just too big for us poor saps to manage.’

Andres gazed at him challengingly. ‘A bit late to say that now, Diluc!’

‘Of course it’s not just numbers but our population’s genetic health that we have to think about,’ pointed out Ruul. This lanky, serious man was the Ship’s senior geneticist. ‘We’ve already started, of course. All of us went through genetic screening before we were selected. There are only two hundred of us, but we’re as genetically diverse a sample of Port Sol’s population as possible. We should avoid the founder effect - none of us has a genetically transmitted disease to be spread through the population - and, provided we exert some kind of control over breeding partnerships, we should be able to avoid genetic drift, where defective copies of a gene cluster.’

Diluc looked faintly disgusted. “‘Control over breeding partnerships”? What kind of language is that?’

Andres snapped, ‘The kind of language we’re going to have to embrace if we’re to survive. We must control reproductive strategies. Remember, on this Ship the purpose of having children is not for the joy of it or similar primate rewards, but to maintain the crew’s population levels and genetic health, and thereby to see through our mission.’ She eyed Diluc. ‘Oh, I’m not against comfort. I was human once! But we are going to have to separate companionship needs from breeding requirements.’ She glanced around. ‘I’m sure you are all smart enough to have figured that out for yourselves. But even this isn’t enough, if the mission objectives are to be ensured.’

Diluc said, ‘It isn’t?’

‘Of course not. This is a desperately small universe. We will always rely on the Ship’s systems, and mistakes or deviances will be punished by catastrophe - for as long as the mission lasts. Non-modified human lifespans average out at around a century; we just haven’t evolved to think further. But a century is but a moment for our mission. We must future-proof; I’ve said it over and over. And to do that we will need a continuity of memory, purpose and control far beyond the century-long horizons of our transients.’

Transients: it was the first time Rusel had heard her use that word.

He thought he saw where all this was leading. He said carefully, ‘Port Sol was not a normal human society. With respect. Because it had you pharaohs at its heart.’

‘Yes,’ she said approvingly, her small face expressionless. ‘And that is the key.’ She lifted her hand before her face and studied it. ‘Two centuries ago the Qax Governor made me ageless. Well, I served the Qax - but my deeper purpose was always to serve mankind. I fled Earth, with others, to escape the Qax. Port Sol was always a refuge for the undying. Now I have had to flee Sol system itself to escape my fellow human beings. But I continue to serve mankind. And it is the continuity I provide, a continuity that transcends human timescales, that will enable this mission to succeed, where even Michael Poole failed.’

Diluc pulled a face. ‘What do you want from us - to worship you as a god?’

There were gasps; you didn’t speak to a pharaoh like that. But Andres seemed unfazed. ‘A god? No - though a little awe from you wouldn’t come amiss, Diluc. And anyhow, it probably won’t be me. Remember, it wasn’t a human agency that gave me my anti-ageing treatments, but the Qax . . .’

The Qax’s own body architecture had nothing in common with humanity’s. They were technically advanced, but their medicinal manipulation of their human subjects was always crude.

‘The success rate was only ever some forty per cent,’ Andres said. She inspected her hand, pulling at slack skin. ‘Oh, I would dearly love to live through this mission, all fifty millennia of it, and see it through to its conclusion. But I fear that’s unlikely to happen.’ She gazed around at them. ‘I can’t do this alone; that’s the bottom line. I will need help.’

Diluc suddenly saw it, and his mouth dropped open. ‘You aren’t serious.’

‘I’m afraid so. It is necessary for the good of the mission that some of the people in this room do not die.’

Ruul the geneticist unfolded his tall frame from his chair. ‘We believe it’s possible. We have the Qax technology.’ Without drama, he held up a yellow pill.

There was a long silence.

Andres smiled coldly. ‘This is no privilege. We can’t afford to die. We must remember, while everybody else forgets.

‘And we must manage. We must achieve total social control - control over every significant aspect of our crew’s lives - and we must govern their children’s lives just as tightly, as far as we can see ahead. Society has to be as rigid as the bulkheads which contain it. Oh, we can give the crew freedom within limits! But we need to enforce social arrangements in which conflict is reduced to negligible, appropriate skill levels kept up - and, most importantly, a duty of maintenance of the Ship is hammered home into every individual at birth. That is why a long-lived elite must ensure perfect continuity and complete control.’

Rusel said, ‘Elite? And what about the rights of those you call the transients? We pharaohs would be taking away all meaningful choice from them - and their children, and their children’s children.’

‘Rights? Rights?’ She loomed over him. ‘Rusel, a transient’s only purpose is to live, reproduce and die in an orderly fashion, thus preserving her genes to the far future. There is no room on this Ship for democracy, no space for love! A transient is just a conduit for her genes. She has no rights, any more than a bit of pipe that carries water from source to sink. Surely you thought this through. When we get to Canis Major, when we find a world to live on, when again we have an environment of surplus - then we can talk about rights. But in the meantime we will control.’ Her expression was complex. ‘But you must see that we will control through love.’

Diluc gaped. ‘Love?’

‘The Qax technology was based on genetic manipulation. We pharaohs were promised that our gift would be passed on to our children. And we had those children! But we pharaohs rarely bred true. I once had a child myself. She did not survive.’ She hesitated, just for a second. Then she went on, ‘But by now there are genes for immortality, or at least longevity, scattered through the human population - even among you. Do you see now why we had to build these arks - why we couldn’t flee and abandon you, or just take frozen zygotes or eggs?’ She spread her hands wide. ‘Because you are my children, and I love you.’

Nobody moved. Rusel thought he could see tears in her stony eyes. She is grotesque, he thought.

Diluc said carefully, ‘Pharaoh, would I be able to bring Tila with me? And our children, if we have them?’

‘I’m sorry,’ she said gently. ‘Tila doesn’t qualify. Besides, the social structure simply wouldn’t be sustainable if—’

‘Then count me out.’ Diluc stood up.

She nodded. ‘I’m sure you won’t be the only one. Believe me, this is no gift I’m offering you. Longevity is a heavy burden.’

Diluc turned to Rusel. ‘Brother, are you coming with me?’

Rusel closed his eyes. The thought of his eventual death had actually been a comfort to him - a healing of his inner wounds, a lifting of the guilt he knew he would carry throughout his life. Now even the prospect of death was being taken away, to be replaced by nothing but an indefinite extension of duty. But he had to take it on, he saw. As Lora herself had told him, he had to live on, like a machine, and fulfil his function. That was why he was here; only that way could he atone.

He looked up at Diluc. ‘I’m sorry,’ he said.

Complex emotions crossed his brother’s face: anger, despair, perhaps a kind of thwarted love. He turned and left the room.

Andres behaved as if Diluc had never existed.

‘We will always have to combat cultural drift,’ she said. ‘It is the blight of the generation starship. Already we have some pregnancies; soon we will have the first children, who will live and die knowing nothing but this Ship. And in a few generations - well, you can guess the rest. First you forget where you’re going. Then you forget you’re going anywhere. Then you forget you’re on a damn ship, and start to think the vessel is the whole universe. And so forth! Soon nothing is left but a rotten apple full of worms, falling through the void. Even the great engineer Michael Poole suffered this; a fifteen-hundred-year generation starship he designed - the first Great Northern - barely limped home. Oh, every so often you might have a glorious moment as some cannibalistic savage climbs the decks and peers out in awe at the stars, but that’s no consolation for the loss of the mission.

‘Well, not this time. You engineers will know we’re almost at the end of our GUTdrive cruise phase; the propellant ice is almost exhausted. And that means the Ship’s hull is exposed.’ She clapped her hands - and, to more gasps from the crew, the amphitheatre’s floor suddenly turned transparent.

Rusel was seated over a floor of stars; something inside him cringed.

Andres smiled at their reaction. ‘Soon we will leave the plane of the Galaxy, and what a sight that will be. In a transparent hull our crew will never be able to forget they are on a Ship. There will be no conceptual breakthroughs on my watch!’

IV

With the ice exhausted, the Ship’s banks of engines were shut down. From now on a dark matter ramjet would provide a comparatively gentle but enduring thrust.

Dark matter constituted most of the universe’s store of mass, with ‘light matter’ - the stuff of bodies and ships and stars - a mere trace. The key advantage of dark matter for the Ship’s mission planners was that it was found in thick quantities far beyond the visible disc of the Galaxy, and would be a plentiful fuel source throughout the voyage. But dark matter interacted with its light counterpart only through gravity. So now invisible wings of gravitational force unfolded ahead of the Ship. Spanning thousands of kilometres, these acted as a scoop to draw dark matter into the hollow centre of the torus-shaped Ship. There, concentrated, much of it was annihilated and induced to give up its mass-energy, which in turn drove a residuum out of the Ship as reaction mass.

Thus the Ship ploughed on into the dark.

Once again the Ship was rebuilt. The acceleration provided by the dark matter ramjet was much lower than the ice rockets, and so the Ship was spun about its axis, to provide artificial gravity through centrifugal force. It was an ancient solution and a crude one - but it worked, and ought to require little maintenance in the future.

The spin-up was itself a spectacular milestone, a great swivelling as floors became walls and walls became ceilings. The transparent floor of the acceleration-couch amphitheatre became a wall full of stars, whose cool emptiness Rusel grew to like.

Meanwhile the new ‘Elders’, the ten of them who had accepted Andres’s challenge, began their course of treatment. The procedure was administered by geneticist Ruul and a woman called Selur, the Ship’s senior doctor. The medics took the process slowly enough to catch any adverse reactions, or so they hoped. For Rusel it was painless enough, just injections and tablets, and he tried not to think about the alien nano-probes embedding themselves in his system, cleaning out ageing toxins, repairing cellular damage, rewiring his very genome.

His work continued to be absorbing, and when he had spare time he immersed himself in studies. All the crew were generalists to some degree, but the ten new Elders were expected to be a repository of memory and wisdom far beyond a human lifespan. So they all studied everything, and they learned from each other.

Rusel began with the disciplines he imagined would be most essential in the future. He studied medicine; anthropology, sociology and ethics; ecosynthesis and all aspects of the Ship’s life-support machinery; the workings of the Ship’s propulsion systems; techniques of colonisation; and the geography of the Galaxy and its satellites. He also buttonholed Andres herself and soaked up her knowledge of human history. Meanwhile, Qax-derived nano-systems were so prevalent throughout the Ship that Rusel’s own expertise was much in demand.

His days passed in a dream, as if time itself flowed differently for him now. His major goal continued to be to use up as much of his conscious time as possible with work. The studying was infinitely expandable, and very satisfying to his naturally acquisitive mind. He found he was able to immerse himself in esoteric aspects of one discipline or another for days on end, as if he was an abstract intellect, almost forgetting who he was.

The Elders’ placid lives were not without disturbance, however. The Qax biotechnology was far from perfect. In the first year of treatment one man suffered kidney failure; he survived, but had to be taken out of the programme.

And it was a great shock to all the Elders when geneticist Ruul himself succumbed to a ferocious cancer, as the technological rebuilding of his cells went awry.

The day after Ruul’s death, as the Elders adjusted to the loss of his competence and dry humour, Rusel decided he needed a break. He walked out of the Elders’ huddled quarters and through the body of the Ship, heading for the area where his brother had set up his own home with Tila.

On all the Ship’s cylindrical decks, the interior geography had been filled by corridors and cabins, clustered in concentric circles around little open plazas - ‘village squares’. Rusel knew the social theory: the Ship was supposed to be loosely partitioned into village-sized communities, but he quickly got lost in the detail; the layout of walls and floors and false ceilings was changed again and again as the crew sorted out their environment.

At last he came to the right doorway on the right corridor. He was about to knock when a boy, aged about five with a shock of thick black hair, rocketed out of the open door and ran between Rusel’s legs. The kid wore a bland Ship’s-issue coverall, long overdue for recycling judging by its grime.

This must be Tomi, Rusel thought, Diluc’s eldest. Child and Elder silently appraised each other. Then the kid stuck out his tongue and ran back into the cabin.

In a moment Diluc came bustling out of the door, wiping his hands on a towel. ‘Look, what in Lethe’s going on—Rusel! It’s you. Welcome, welcome!’

Rusel embraced his brother. Diluc smelt of baby sick, cooking and sweat, and Rusel was shocked to see a streak of grey in his brother’s hair. Perhaps Rusel had been locked away in his studies longer than he had realised.

Diluc led Rusel into his home. It was a complex of five small interconnected cabins, including a kitchen and bathroom. Somebody had been weaving tapestries; gaudy, space-filling abstract patterns filled one wall.

Rusel sat on a sofa adapted from an acceleration couch, and accepted a slug of some kind of liquor. He said, ‘I’m sorry I frightened Tomi. I suppose I’ve let myself become a stranger.’

Diluc raised an eyebrow. ‘Two things about that. Not so much “stranger” as “strange”.’ He brushed his hand over his scalp.

Rusel involuntarily copied the gesture, and felt bare skin. He had long forgotten that the first side-effect of the pharaoh treatment had been the loss of his hair; his head was as bald as Andres’s. Surrounded all day by the other Elders, Rusel had got used to it, he supposed. He said dryly, ‘Next time I’ll wear a wig. What’s the second thing I got wrong?’

‘That isn’t Tomi. Tomi was our first. He’s eight now. That was little Rus, as we call him. He’s five.’

‘Five?’ But Rusel had attended the baby Rusel’s naming ceremony. It seemed like yesterday.

‘And now we’re due for another naming. We’ve missed you, Rus.’

Rusel felt as if his life was slipping away. ‘I’m sorry.’

Tila came bustling in, with an awestruck little Rus in tow, and an infant in her arms. She too seemed suddenly to have aged; she had put on weight, and her face was lined by fine wrinkles. She said that Tomi was preparing a meal - of course Uncle Rusel would stay to eat, wouldn’t he? - and she sat down with the men and accepted a drink.

They talked of inconsequentials, and of their lives.

Diluc, having stormed out of Andres’s informal council, had become something of a leader in his own new community. Andres had ordered that the two-hundred-strong crew should be dispersed to live in close-knit ‘tribes’ of twenty or so, each lodged in a ‘village’ of corridors and cabins. There were to be looser links between the tribes, for such purposes as finding marriage or breeding partners. Thus the Ship was united in a single ‘clan’. Andres said this social structure was the most common form encountered among humans ‘in the wild’, as she put it, all the way back to pretechnological days on Earth, and was the most likely to be stable in the long run. Whether or not that was true, things had stayed stable so far.

Andres had also specified the kind of government each tribe should aspire to. In such a small world each individual should be cherished for her unique skills, and for the value of the education invested in her. People were interdependent, said Andres, and the way they governed themselves should reflect that. Even democracy wouldn’t do, as in a society of valued individuals the subjection of a minority to the will of a majority must be a bad thing. So Diluc’s tribe ran by consensus.

‘We talk and talk,’ Diluc said with a rueful grin, ‘until we all agree. Takes hours, sometimes. Once, the whole of the night watch.’

Tila snorted. ‘Don’t tell me you don’t like it that way. You always did like the sound of your own voice!’

The most important and difficult decisions the tribe had to make concerned reproduction, Most adults settled down into more-or-less monogamous marriages. But there had to be a separation between marriages for companionship and liaisons for reproduction; the gene pool was too small to allow matings for such trivial reasons as love.

Diluc showed Rusel a draft of a ‘social contract’ he was preparing to capture all this. ‘First, on reaching adulthood you submit yourself to the needs of the group as a whole. For instance your choice of career depends on what we need as much as what you want to do. Second, you agree to have kids only as the need allows. If we’re short of the optimum population level, you might have three or four or five, whether you want them or not, to bring up the numbers; if we’re over the target, you might have none at all and die childless. Third, you agree to postpone parenthood for as long as possible, and to keep working as long as possible. That way you maximise the investment the tribe has made in educating you. Fourth, you can select your own breeding-spouse, who may be the same as your companionship-spouse—’

‘We were lucky,’ Tila said fervently.

‘But she can’t be closer than a second cousin. And you have to submit to having your choice approved by the Elders. That’s you.’ He grinned at Rusel. ‘Your match will be screened for genetic desirability, and to maximise the freshness of the gene pool - all of that. And finally, if despite everything you’re unlucky enough to have been born with some inheritable defect that might, if propagated, damage the Ship’s chances of completing its mission, you agree not to breed at all. Your genetic line stops with you.’

Rusel frowned. ‘That’s eugenics.’

Diluc shrugged. ‘What else can we do?’

Diluc hadn’t studied Earth history, as Elder-educated Rusel now had, and without that perspective, Rusel realised, that word carried for him none of the horrific connotations it had once borne. As Diluc had implied, they had little choice anyhow given the situation they were in. Besides, eugenics through arranged couplings was lower-tech than genetic engineering: more future-proofing.

Rusel studied the draft contract. ‘And what happens if somebody breaks the rules?’

Diluc was uncomfortable; suddenly Rusel was aware that he was an Elder, as well as this man’s brother. ‘We’ll cross that bridge when we come to it,’ Diluc said. ‘Look, Rus, we don’t have police here, and we don’t have room for jails. Besides, everybody really is essential to the community as a whole. We can’t coerce. We work by persuasion; we hope that such situations will be easily resolved.’

Diluc talked of personal things too: of the progress of his boys at school, how Tomi had always hated the hour’s wall-cleaning he had to put in each day, while little Rus loved it for the friends he was making.

‘They are good kids,’ Rusel said.

‘Yes. And you need to see more of them,’ Diluc said pointedly. ‘But, you know, Rus, they’re not like us. They are the first Shipborn generation. They are different. To them, all our stories of Port Sol and Canis Major are so many legends of places they will never see. This Ship is their world, not ours: we, born elsewhere, are aliens here. You know, I keep thinking we’ve bitten off more than we can chew. For all Andres’s planning, already things are drifting. No wonder generation starships always fail!’

Rusel tried to respond to their openness by giving them something of himself. But he found he had little to say. His mind was full of studying, but there was very little human incident in his life. It was if he hadn’t been alive at all, he thought with dismay.

Diluc was appalled to hear of Ruul’s death. ‘That pompous geneticist - I suppose in a way it’s fitting he should be the first to go. But don’t let it take you, brother.’ Impulsively he crossed to Rusel and rested his hand on his brother’s shoulder. ‘You know, all this is enough for me: Tila, the kids, the home we’re building together. It’s good to know that our lives serve a higher goal, but this is all I need to make me happy. Maybe I don’t have much imagination, you think?’

Or maybe you’re more human than I am, Rusel thought. ‘We must all make our choices,’ he said.

Diluc said carefully, ‘But you can still make a different choice.’

‘What do you mean?’

He leaned forward. ‘Why don’t you give it up, Rus? This crappy old Qax nano-medicine, this dreadful anti-ageing - you’re still young; you could come out of there, flush the shit out of your system, grow your hair back, find some nice woman to make you happy again . . .’

Rusel tried to keep his face expressionless, but he failed.

Diluc backed off. ‘Sorry. You still remember Lora.’

‘I always will. I can’t help it.’

‘We’ve all been through an extraordinary experience,’ Tila said. ‘I suppose we all react differently.’

‘Yes.’ Tila, he remembered, had left behind a child.

Diluc looked into his eyes. ‘You never will come out, will you? Because you’ll never be able to cast off that big sack of guilt on your back.’

Rusel smiled. ‘Is it that obvious?’

Tila was a gracious hostess. She perceived his discomfort, and they began to talk of old times, of the days on Port Sol. But Rusel was relieved when Tomi came in to announce that the meal was ready, relieved to hurry through the food and get away, relieved to shut himself away once more in the bloodless monastic calm of his studying.

V

He would remember that difficult visit again, much later, when a boy came to find him.

As time passed, the Elders withdrew further from the crew. They requisitioned their own sealed-off living area. It was close to the Ship’s axis where the artificial gravity was a little lower than further out, a sop to muscles and bones expected to weaken with the centuries. Andres humorously called this refuge the ‘Cloister’. And the Elders were spared the routine chores, even the cleaning, to which the rest of the crew were subject. Soon it was hard to avoid the feeling that the crew were only there to serve the Elders.

Of course it was all part of Andres’s grand social design that there should eventually be an ‘awe gap’, as she put it, between Elders and transients. But Rusel wondered if a certain distancing was inevitable anyhow. The differential ageing of transients and Elders became apparent surprisingly quickly. When an Elder met a transient she saw a face that would soon crumble with age and vanish, while the transient saw a mysteriously unchanging figure who would see events that transpired long after the transient was dead. Rusel watched as friendships dissolved, even love affairs evaporated, under this stress.

However the increasingly isolated Elders, thrown on each other’s company, were no chummy club. They were all bright, ambitious people; they wouldn’t have been filtered out for Andres’s inner circle otherwise, and there was always a certain tension and bickering. Doctor Selur remarked sourly that it was like being stuck with a bunch of jealous academics, for ever.

But the Elders were also cautious of each other, Rusel thought. Always at the back of his mind was the thought that he would have to live with these people for a long time. So he strove not to make any enemies - and conversely not to get too close to anyone. Eternity with a lover was one thing, but with an ex-lover it would be hellish. Better that things were insipid, but tolerable.

Life settled down. In the calm of the Cloister, time passed smoothly, painlessly.

One day a boy came knocking timorously, asking for Rusel. He was aged about sixteen.

Rusel thought he recognised him. He had spent a long time on his own, and his social skills were rusty, but he tried to focus and greet the boy warmly. ‘Tomi! It’s so long since I saw you.’

The boy’s eyes were round. ‘My name is Poro, sir.’

Rusel frowned. ‘But that day I came to visit - you made us all a meal, me and Diluc and Tila, while little Rus played . . .’ But that was long ago, he told himself, he wasn’t sure how long, and he fell silent.

The boy seemed to have been prepared for this. ‘My name is Poro,’ he said firmly. ‘Tomi was—’

‘Your father.’

‘My grandfather.’

So this was Diluc’s great-grandson. Lethe, how long have I spent inside this box?

The boy was looking around the Cloister. His eyes were unblinking, his mouth pulled back in a kind of nervous grin. None of the Elders was hot on empathy, especially with transients, but suddenly Rusel felt as if he saw this place through this child’s eyes.

The Cloister was like a library, perhaps. Or a hospital room. The Elders sat in their chairs or walked slowly through the silence of the room, their every step calculated to reduce the risk of harm to their fragile, precious bodies. It had been this way since long before Poro had been born, these musty creatures pursuing their cold interests. And I, who once loved Lora when she wasn’t much older than this child, am part of this dusty stillness.

‘What do you want, Poro?’

‘Diluc is ill. He is asking for you.’

‘Diluc . . . ?’

‘Your brother.’

It turned out that Diluc was more than ill; he was dying.

So Rusel went with the boy, stepping outside the confines of the Cloister for the first time in years.

He wasn’t at home out here any more. The original crew had died off steadily, following a demographic curve not terribly different to that they would have endured had they remained on Port Sol. Rusel had grown used to seeing faces he had known since childhood crumple with age and disappear before him. Still, it had been a shock when that first generation reached old age - and, since many of them had been around the same age at launch, their deaths came in a flood.

He knew none of the faces of the younger transients. Everything about the new generations was different: the way they rebuilt the Ship’s internal architecture, their manner with each other, the way they wore their hair - even their language, which was full of a guttural slang. The transients knew him, though, even the youngest. They stared at him with curiosity, or irreverence - or, worst of all, awe.

The basic infrastructure of the Ship itself, of course, remained unchanged. In a way he came to identify with that level of reality much more than with the flickering, fast-paced changes wrought by the transients. Though his senses were slowly dulling - the Qax treatment had slowed his ageing but not stopped it entirely - he felt he was becoming more attuned to the Ship’s subtle vibrations and noises, its mechanical moods and joys. Transients came and went, fiddling with the partitions, and the other Elders were awkward old cusses, but the Ship itself was his constant friend, demanding only his care.

As they walked he saw that the boy had a bruise on his forehead. ‘What happened to you?’

‘Punishment.’ Poro averted his eyes, ashamed. One of his teachers had whacked him with a ruler for ‘impudence’, which turned out to mean asking too-deep questions.

A paradox was emerging in the philosophy of education aboard the Ship. It had been quickly found that learning needed to be restrictive, and that curiosity couldn’t be allowed to go unchecked. The students had to be bright and informed enough to be able to maintain the Ship’s systems. But there was no room for expansion or innovation. There was unusually only one way to do things: you learned it that way.

It was necessary, Rusel knew. You couldn’t have people tinkering. So you learned only what you needed to know, and were taught not to ask any more, not to explore. But he didn’t like the idea of battering students into submission for the ‘crime’ of curiosity. Perhaps he would have a word with Andres about it, get a new policy formulated.

They reached Diluc’s corridor-village.

Before he could see his brother he had to be met by a series of tribe worthies. Burly men and women in drab Ship’s-issue clothing, they gathered with solemn expressions. Their greetings were lengthy and complicated. The transients seemed to be evolving elaborate rituals to be used on every social occasion: meeting, parting, taking meals. Rusel could see the value of such rituals, which used up time, and reduced social friction. But it was hard to keep up with the ever-changing rules. The only constant was that these politeness games always got more elaborate - and it was very easy to get something wrong and give offence.

The worthies looked concerned at the prospective loss of Diluc, as well they might.

Andres’s imposition of ‘rule-by-consensus’ had been less than effective. In some of the Ship’s dozen or so tribes, there was endless jaw-jaw that paralysed decision-making. Elsewhere strong individuals had begun to grasp power, more or less overtly. Andres wasn’t too concerned as long as the job got done, the basic rules obeyed: whoever was in command among the transients had to get the approval of the Elders anyhow, and so Andres and her team were still able to exert a moderating influence.

The situation in Diluc’s tribe had been more subtle, though. As the brother of an Elder Diluc had had a unique charisma, and he had used that power to push his peers to conclusions they might not otherwise have reached. He had been a leader, but of the best sort, Rusel thought, leading from the back, invisibly. Now he was about to be taken away, and his people knew they would miss him.

With the worthies out of the way, the Elder was presented to Diluc’s children, grandchildren, great-grandchildren. All of them went through more elaborate transient-to-Elder rituals, even the smallest children, with an unsmiling intensity Rusel found disturbing.

At last, with reluctance, he entered Diluc’s apartment. The rooms were much as he remembered them, though the tapestries on the wall had changed.

Tila was still alive, though she was bent, her hair white, and her face a crumpled mask. ‘Thank you for coming,’ she whispered, and she took Rusel’s hands in her own. ‘There are so few of us left, you know, so few not Shipborn. And he did keep asking for you.’

Rusel pressed her hand, reserved, awkward. He felt out of practice with people, with emotions; before this broken-hearted old woman he felt utterly inadequate.

Diluc himself lay on a bed, covered by a worn blanket. Rusel was shocked by how his brother had imploded with age. And he could see, even through the blanket, the swelling of the stomach tumour that was killing him.

He had thought Diluc was sleeping. But his brother opened one eye. ‘Hello, Rusel,’ he said, his voice a croak. ‘You bastard.’

‘I’m sorry—’

‘You haven’t been here in fifty years.’

‘Not that long.’

‘Fifty years! Fifty years! It’s not as if—’ He broke up in coughing. ‘As if it’s that big a Ship . . .’

They talked, as they had talked before. Diluc told rambling anecdotes about his grandchildren and great-grandchildren, all properly genetically selected, all wonderful kids.

Rusel had to tell him of a cull of the Elders.

It had had a variety of causes, according to Doctor Selur, but Andres had sniffed at that. ‘I’ve seen it before. Call it a death wish,’ she had said. ‘You reach an age where your body knows it’s time to die. You accept it. Maybe it’s some kind of neural programming, a comfort as we face the inevitable.’ She cackled; she was ageing too, and was now toothless. ‘The Qax treatments don’t do anything about it. And it carries away more would-be immortals than you’d imagine. Strange, isn’t it? That longevity should turn out to be a matter of the mind as much as the body.’

Rusel had spent some years in faint trepidation, wondering if and when his own dark-seeking mental programming might kick in. But it never did, and he wondered if he had some unsuspected strength - or, perhaps, a deficiency.

Now Diluc grimaced. ‘So even immortals die.’ He reached out his hand. Rusel took it; the bones were frail, the flesh almost vanished. ‘Look after them,’ Diluc said.

‘Who?’

‘Everybody. You know. And look after yourself.’ He looked up at his brother, and Rusel saw pity in his brother’s eyes - pity for him, from a withered, dying man.

He could bear to stay only a few minutes more. He would never see his brother again.

He tried to talk over his feelings about Diluc’s death with the Captain. But Andres was dismissive. ‘Diluc was a coward who shunned his duty,’ she said. ‘Anyhow, better when the first crew have all gone. They always saw us as peers, to some extent. So they resisted our ideas, our leadership; it was natural. We’re totally alien to the new sort, and that will make them more malleable.

‘And the new lot never suffered the trauma of seeing Port Sol trashed before their eyes. The psychological trauma ran deep, Rusel; you aren’t the only one . . . This new batch are healthier, adjusted to the environment of the Ship, because they’ve known nothing else. When there’s only them left, we’ll be able to get things shaken down properly around here at last. You’ll see.’

With relief Rusel returned to his studies, away from the complications of humanity. Once more time flowed smoothly past him, and that difficult day receded down the dimming corridors of his memory.

No more relatives came to see him, ever again.

VI

‘. . . Rusel. Rusel!’ The voice was harsh - Andres’s voice.

Sleep was deep these days, and it took him an age to emerge. And as he opened himself to the light he swam up through layers of dream and memory, until he became confused about what was real and what wasn’t. He always knew where he was, of course, even in his deepest sleep. He was on the Ship, his drifting tomb. But he could never remember when he was.

He tried to sit up. The Couch responded to his feeble movements, and its back smoothly lifted him upright. He peered around in the dim, golden light of the Cloister. There were three Couches, great bulky mechanical devices half bed and half medical support system: only three, because only three of the Elders stayed alive.

Somebody was moving around him. It was a transient, of course, a young woman, a nurse. He didn’t recognise her; she was new since he’d last been awake. She kept her eyes averted, and her hands fluttered through an elaborate greetings-with-apology ritual. He dismissed her with a curt gesture; you could eat up your entire day with such flim-flam.

Andres was watching him, her eyes sharp in her ruin of a face. She looked like a huge bug in her cocoon of blankets.

‘Well?’ he snapped.

‘You are drooling,’ she said mildly. ‘Not in front of the transients, Rusel.’

Irritated, he wiped his chin with his sleeve.

‘Oh,’ she said, her tone unchanged, ‘and Selur died.’

That news, so casually delivered, was like a punch in the throat. He turned clumsily, weighed down by blankets and life-sustaining equipment. The doctor’s Couch was surrounded by transients who were removing her mummy-like body. Working in silence, cautiously, reverently, they were trembling, he saw dimly.

‘I never did like her much,’ Rusel said.

‘You’ve said that before. Many times.’

‘I’ll miss her, though.’

‘Yes. And then there were two. Rusel, we need to talk. We need a new strategy to deal with the transients. We’re supposed to be figures of awe. Look at us. Look at poor Selur! We can’t let them see us like this again.’

He glanced cautiously at the transient nurses.

‘Don’t worry,’ Andres said. ‘They can’t understand. Linguistic drift. I don’t think we should allow transients in here any more. The machines can sustain us. Lethe knows there are enough spare parts, now we have so many empty Couches! What I suggest is—’

‘Stow it,’ he said crossly. ‘You’re always the same, you old witch. You always want to jam a solution down my throat before I even know what the problem is. Let me gather my thoughts.’

‘Stow it, stow it,’ she parroted, grotesquely.

‘Shut up.’ He closed his eyes to exclude her, and laid back in his Couch. Through the implant in the back of his skull he allowed data from his body, the Ship, and the universe beyond filter into his sensorium.

His body first, of course, the slowly failing biomachinery that had become his prison. The good news was that, more than two centuries after his brother’s death, his slow ageing had bottomed out. Since he had last checked - Lethe, all of a month ago, it seemed like yesterday, how long had he slept this time? - nothing had got significantly worse. But he was stuck in the body of a ninety-year-old man, and a frail old man at that. He slept almost all the time, his intervals of lucidity ever more widely separated, while the Couch fed him, removed his waste, gently turned him to and fro and manipulated his stick-thin limbs. Oh, and every few weeks he received a blood transfusion, an offering to the Elders from the grateful transients outside the Cloister. He may as well have been a coma victim, he thought grumpily.

His age was meaningless, his condition boring. Briskly he moved on.

His Virtual viewpoint roamed through the Ship. Despite the passage of centuries, the physical layout of the corridor-village that had been Diluc’s was the same, save for detail, the same knots of corridors around the ‘village square’. But the people had changed, as they always did, youth blossoming, old age crumbling.

The Autarch he remembered from his last inspection was still in place. He was a big bruiser who called himself Ruul, in subtle defiance of various inhibitions against taking the name of an Elder, even one long dead. He at least didn’t look to have aged much since Rusel’s last inspection. Flanked by two of his wives, Ruul received a queue of supplicants, all seeking the Autarch’s ‘wisdom’ concerning some petty problem or other. Ruul’s judgements were brisk and efficient, and as Rusel listened - though the time-drifted language was hard to decipher - he couldn’t spot any immediate errors of doctrine in the Autarch’s summary harshness.

He allowed his point of view to move on.

He watched the villagers go about their business. Four of them were scrubbing the walls clean of dirt, as they took turns to do every day. Two plump-looking worthies were discussing a matter of etiquette, their mannerisms complex and time-consuming. There were some new bits of artwork on the walls, many of them fool-the-eye depth-perspective paintings, designed to make the Ship’s corridors look bigger than they were. One woman was tending a ‘garden’ of bits of waste polymer, combing elaborate formations into it with a small metal rake. These transients, Shipborn for generations, had never heard of Zen gardens; they had rediscovered this small-world art form for themselves.

A little group of children was being taught to disassemble and maintain an air-duct fan; they chanted the names of its parts, learning by rote. They would be taught nothing more, Rusel knew. There was no element of principle here: nothing about how the fan as a machine worked, or how it fitted into the greater systems of the Ship itself. You only learned what you needed to know.

As he surveyed the village, statistics rolled past his enhanced vision in a shining column. Everything was nominal, if you took a wider perspective. Maintenance routines were being kept up satisfactorily. Reproduction rules, enforced by the Autarch and his peers in the other villages, were largely being adhered to, and there was a reasonable genetic mix.

The situation was stable. But in Diluc’s village, only the Autarch was free.

Andres’s uncharacteristically naïve dream of respectful communities governing themselves by consensus had barely outlasted the death of Diluc. In the villages strong characters had quickly taken control, and in most cases had installed themselves and their families as hereditary rulers. Andres had grumbled at that, but it was an obviously stable social system, and in the end the Elders, in subtle ways, lent the Autarchs their own mystical authority.

The Autarchs were slowly drifting away from their subject populations, though.

Some ‘transients’ had always proven to be rather longer-lived than others. It seemed that the Qax’s tampering with the genomes of their pharaohs had indeed been passed on to subsequent generations, if imperfectly, and that gene complex, a tendency for longevity, was gradually expressing itself. Indeed the Autarchs actively sought out breeding partners for themselves who came from families that showed such tendencies.

So, with time, the Autarchs and their offspring were ageing more slowly than their transient subjects.

It was just natural selection, argued Andres. People had always acquired power so that their genes could be favoured. Traditionally you would propagate your genes by doing your best to outbreed your subjects. But if you were an Autarch, in the confines of the Ship, what were you to do? There was obviously no room here for a swarm of princes, bastards or otherwise. Besides, the Elders’ genetic-health rules wouldn’t allow any such thing. So the Autarchs were seeking to dominate their populations with their own long lives, not numbers of offspring.

Andres seemed to find all this merely intellectually interesting, a working-out of genetic games theory. Rusel wondered what would happen if this went on.

He continued his random wandering. Everybody was busy, intent on their affairs. Some even seemed happy. But it all looked drab to Rusel, the villagers dressed in colourless Ship’s-issue clothing, their lives bounded by the polished-smooth bulkheads of the Ship. Even their language was dull, and becoming duller. The transients had no words for ‘horizon’ or ‘sky’ - but as if in compensation they had over forty words describing degrees of love.

He allowed his consciousness to return to his own body. When he surfaced, he found Andres watching him, as she so often did.

‘We need a new way to interface with the transients,’ she said again. ‘Some of the Autarchs are tough customers, Rusel. If they start to believe we’re weak - for instance, if we sleep for three days before delivering the answer to the simplest question—’

‘I understand. We can’t let the transients see us.’ He sighed, irritated. ‘But what else can we do? Delivering edicts through disembodied voices isn’t going to wash. If they don’t see us they will soon forget who we are.’ ‘Soon’, in the language of the Elders, meaning in another generation or two.

‘Right,’ she snapped. ‘So we have to repersonalise our authority. What do you think of this?’ She gestured feebly, and a Virtual coalesced in the air over her head.

It showed Rusel. Here he was as a young man, up to his elbows in nanofood banks, labouring to make the Ship sound for its long journey. Here he was as a young-ish Elder, bald as ice, administering advice to grateful transients. There were even images of him from the vanishingly remote days before the launch, images of him with a smiling Lora.

‘Where did you get this stuff?’

She sniffed. ‘The Ship’s log. Your own archive. Come on, Rusel, we hardly have any secrets from each other after all this time! Pretty girl, though.’

‘What are you intending to do with this?’

‘We’ll show it to the transients. We’ll show you at your best, Rusel, you at the peak of your powers, you walking the same corridors they walk now - you as a human being, yet more than human. That’s what we want: engagement with their petty lives, empathy, yet awe. We’ll put a face to your voice.’

He closed his eyes. It made sense, of course; Andres’s logic was grim, but always valid. ‘But why me? It would be better if both of us—’

‘That wouldn’t be wise,’ she said. ‘I wouldn’t want them to see me die.’

It took him a while to work out that she meant that she, Andres, the first of the Elders, was failing at last. Rusel found this impossible to take in: her death would be to have a buttress of the universe knocked away. ‘But you won’t see the destination,’ he said peevishly, as if she was making a bad choice.

‘No,’ she said hoarsely. ‘But the Mayflower will get there! Look around, Rusel. The Ship is functioning flawlessly. Our designed society is stable and doing its job of preserving the bloodlines. And you, you were always the brightest of all. You will see it through. That’s enough for me.’

It was true, Rusel supposed. Her design was fulfilled; the Ship and its crew were working now just as Andres had always dreamed they should. But only two hundred and fifty years had worn away, only half of one per cent of the awesome desert of time he must cross to reach Canis Major - and now, it seemed, he was going to have to make the rest of that journey alone.

‘No, not alone,’ said Andres. ‘You’ll always have the Ship . . .’

Yes, the Ship, his constant companion. Suddenly he longed to escape from the endless complications of humanity and immerse himself in its huge technological calm.

He lay back in his Couch and allowed his mind to roam once more. This time his awareness drifted away from the bright warm human bubble at the Ship’s heart, out through the crowded torus of the hull to the realm of the pulsing ramjet engines, the wispy gravitational wings behind which the Ship sailed, and the vast spaces beyond. The Ship had covered only a fraction of its epic journey, but already it was climbing out of the galactic plane and the Core, the crowded heart of the Galaxy, rose like a sun from the dust-strewn lanes of the spiral arms. It was a stunning, comforting sight.

By the time he came back from his intergalactic dreaming, Andres was gone, her Couch disassembled for spare parts, her body removed to the cycling tanks.

VII

Rusel was woken from his long slumber by the face of a boy, a face twisted with anger - an anger directed at him.

In retrospect Rusel should have seen the rebellion coming. All the indicators had been there: the drift of the transients’ social structures, the gathering tensions. It was bound to happen.

But it was so hard for him to pay attention to the brief lives of these transients, their incomprehensible language and customs, their petty concerns and squabbling. After all, Hilin was a boy of the forty-fifth generation since launch: forty-five generations. Lethe, nearly a thousand years . . .

The exploits of Hilin, though, forced themselves on his attention.

Hilin was sixteen years old when it all began. He had been born in Diluc’s corridor-village.

By now the Autarchs of the different villages had intermarried to form a seamless web of power. They lived on average twice as long as their subjects, and had established a monopoly on the Ship’s water supply. A water empire ruled by gerontocrats: their control was total.

Hilin was not one of the local Autarch’s brood; his family were poor and powerless, like all the Autarch’s subjects. But they seemed to accept their lot. As he played in corridors whose polymer floors were rutted by generations of passing feet, Hilin emerged as a bright, happy child. He seemed compliant when he was young, cheerfully swabbing the bulkheads when it was his turn, and accepting the cuffs of his teachers when he asked impudent questions.

He had always been oddly fascinated by the figure of Rusel himself - or rather the semi-mythical presence portrayed to the villagers through the cycling Virtual storyboards. Hilin soaked up the story of the noble Elder who had been forced to choose between a life of unending duty and his beloved Lora, eventually becoming an undying model to those he ruled.

As he had grown, Hilin had flourished educationally. At fourteen he was inducted into an elite caste. As intellectual standards declined, literacy had largely been abandoned, and ancient manuals had anyhow crumbled to dust. So these monkish thinkers now committed to memory every significant commandment regarding the workings of the Ship and their own society. You would start on this vital project at fourteen, and wouldn’t expect to be done until you were in your fifties, by which time a new generation of rememberers was ready to take over anyhow.

Rusel dryly called these patient thinkers Druids: he wasn’t interested in the transients’ own names for themselves, which would change in an eye-blink generation anyhow. He had certainly approved of this practice when it emerged. All this endless memorising was a marvellous way to use up pointless lives - and it established a power-base to rival the Autarchs.

Again Hilin had flourished, and he passed one Druidic assessment after another. Even a torrid romance with Sale, a girl from a neighbouring village, didn’t distract him from his studies.

When the time came, the couple asked their families for leave to form a companionship-marriage, which was granted. They went to the Autarch for permission to have children. To their delight, it turned out their genetic make-ups, as mapped in the Druids’ capacious memories, were compatible enough to allow this too.

But even so the Druids forbade the union.

Hilin, horrified, learned that this was because of the results of his latest Druidic assessment, a test of his general intelligence and potential. He had failed, not by posting too low a score, but too high.

Rusel, brooding, understood. The eugenic elimination of weaknesses had in general been applied wisely. But under the Autarch-Druid duopoly, attempts were made to weed out the overbright, the curious - anybody who might prove rebellious. So, if you were bright, you mustn’t be allowed to breed. Rusel would have stamped out this practice, had he even noticed it. If this went on, the transient population would become passive, listless, easily manipulated by the Autarchs and the Druids, but useless for the mission’s larger purposes.

It was too late for Hilin. He was banned from ever seeing his Sale again. And he was told by the Autarch’s ministers that this was by order of the Elder himself, though Rusel, dreaming his life away, knew nothing about it.

After that Hilin spent long hours in the shrine-like enclosure where Rusel’s Virtuals played out endlessly. He tried to understand. He told himself the Elder’s wisdom surpassed his own; this severance from his lover must be for the best, no matter what pain it caused him. He even tried to draw comfort from what he saw as parallels between his own doomed romance and Rusel and his lost Lora. But understanding didn’t come, and his bewilderment and pain soon blossomed to resentment - and anger.

In his despair, he tried to destroy the shrine of the Elder.

As punishment, the Autarch locked him in a cell for two days. Hilin emerged from his confinement outwardly subdued, inwardly ready to explode.

Rusel would later castigate himself for failing to see the dangers in the situation. But it was so hard to see anything at all now.

His central nervous system was slowly deteriorating, so the Couch informed him. He could still move his arms and legs - he could still walk, even, with a frame - but he felt no sensation in his feet, nothing but the faintest ache in his fingertips. As pain and pleasure alike receded, he felt he was coming loose from the world. When he surfaced into lucidity he was often shocked to find a year had passed like a day, as if his sense of time was becoming logarithmic.

And meanwhile, as he became progressively disconnected from the physical world, his mind was undergoing a reconstruction of its own. After a thousand years his memories, especially the deepest, most precious memories of all, were, like the floors of the Ship’s corridors, worn with use; he was no longer sure if he remembered, or if he only had left memories of memories.

If he couldn’t rely even on memory, if he came adrift from both present and past, what was he? Was he even human any more? Certainly the latest set of transients meant less than nothing to him: why, each of them was made up of the atoms and molecules of her ancestors, cycled through the Ship’s systems forty times or more, shuffled and reshuffled in meaningless combinations. They could not touch his heart in any way.

At least he thought so, until Hilin brought him the girl.

The two of them stood before Rusel’s Virtual shrine, where they believed the Elder’s consciousness must reside. Trying to match the Elder’s own timescales they stayed there for long hours, all but motionless. Hilin’s face was set, pinched with anger and determination. She, though, was composed.

At last Rusel’s lofty attention was snagged by familiarity. The girl was taller than most of the transients, pale, her bones delicate. And her eyes were large, dark, somehow unfocused even as she gazed into unseen imaging systems.

Lora.

It couldn’t be, of course! How could it? Lora had had no family on the Ship. And yet Rusel, half-dreaming, immersed in memory, couldn’t take his eyes off her image.

As Hilin had planned.

And as Rusel gazed helplessly at ‘Lora’s’ face, the uprising broke out all over the Ship. In every village the Autarchs and their families were turned out of their palatial cabins. The Autarchs, having commanded their short-lived flocks for centuries, were quite unprepared, and few resisted; they had no conception such an uprising was even possible. The old rulers and their peculiar children were herded together in a richly robed mass in the Ship’s largest chamber, the upturned amphitheatre where Rusel had long ago endured the launch from Port Sol.

The revolt had been centrally planned, carefully timed, meticulously executed. Despite generations of selective breeding to eliminate initiative and cunning, the transients no longer seemed so sheepish, and in Hilin they had discovered a general. And it was over before the Elder’s attention had turned away from the girl, before he had even noticed.

Now Hilin, king of the corridors, stood before the Elder’s shrine. And he pulled at the face of the girl, the Lora look-alike. It had been a mask, just a mask; Rusel realised shamefully that with such a simple device the boy had manipulated the emotions of a being more than a thousand years old.

A bloody club in his hand, Hilin screamed his defiance at his undying god. The Cloister’s systems translated the boy’s language, after a thousand years quite unlike Rusel’s. ‘You allowed this to happen,’ Hilin yelled. ‘You allowed the Autarchs to feed off us like [untranslatable - body parasites? ]. We wash the decks for them with our blood, while they keep water from our children. And you, you [untranslatable - an obscenity? ] allowed it to happen. And do you know why?’ Hilin stepped closer to the shrine, and his face loomed in Rusel’s vision. ‘Because you don’t exist. Nobody has seen you in centuries - if they ever did! You’re a lie, cooked up by the Autarchs to keep us in our place, that’s what I think. Well, we don’t believe in you any more, not in any of that [untranslatable - faeces? ]. And we’ve thrown out the Autarchs. We are free!’

‘Free’ they were. Hilin and his followers looted the Autarchs’ apartments, and gorged themselves on the food and water the Autarchs had hoarded for themselves, and screwed each other senseless in blithe defiance of genetic-health prohibitions. And not a single deck panel was swabbed down.

After three days, as the chaos showed no signs of abating, Rusel knew that this was the most serious crisis in the Ship’s long history. He had to act. It took him another three days to get ready for his performance, three days mostly taken up with fighting with the inhibiting protocols of his medical equipment.

Then he ordered the Cloister door to open, for the first time in centuries. It actually stuck, dry-welded in place. It finally gave way with a resounding crack, making his entrance even more spectacular than he had planned.

But there was nobody around to witness his incarnation but a small boy, no more than five years old. With his finger planted firmly in one nostril, and his eyes round with surprise, the kid looked heartbreakingly like Tomi, Diluc’s boy, long since dead and fed to the recycling banks.

Rusel was standing, supported by servomechanisms, gamely clutching at a walking frame. He tried to smile at the boy, but he couldn’t feel his own face, and didn’t know if he succeeded. ‘Bring me the chief Druids,’ he said, and a translation whispered in the air around him.

The boy yelled and fled.

The Druids actually knelt before him, covering their faces. He walked very cautiously among them, allowing them even to touch his robe. He wanted to be certain they accepted his reality, to smell the dusty tang of centuries on him. Maybe in their hearts these monkish philosophers, like Hilin, had never really believed in the Elder’s existence. Well, now their messiah had suddenly reincarnated among them.

But Rusel himself saw them as if through a flawed lens; he could hear little, feel less, smell or taste nothing. It was like walking around in a skinsuit, he thought.

He was an angry god, though. The rules of Shipboard life had been broken, he thundered. And he didn’t just mean the recent mess. There must be no more water empires, and no knowledge empires either: the Druids would have to make sure that every child knew the basic rules, of Ship maintenance and genetic-health breeding.

He ordered that the Autarchs should not be returned to their seats of power. Instead, the governing would be done, for this generation, by a Druid - he picked out one terrified-looking woman at random. As long as she ruled wisely and well, she would have the Elder’s backing. On her death the people would select a successor, who could not be more closely related to her predecessor than second cousin. No more dynasties.

The old Autarchs and their brood, meanwhile, were to be spared. They would be shut away permanently in their amphitheatre prison, where there were supplies to keep them alive. Rusel believed they and their strange slow-growing children would die off; within a generation, a tick of time, that problem would go away. He had done his share of killing, he thought.

Then he sighed. The worst of it had still to be faced. ‘Bring me Hilin,’ he ordered.

They dragged in the corridor king, tied up with strips of cloth. He had been assaulted, Rusel saw; his face was battered and one arm seemed broken. This erstwhile rebel was already being punished for his blasphemy, then, by those who sought the favour of the Elder. But Hilin faced Rusel defiantly, strength and intelligence showing in his face. Rusel’s scarred heart ached a little more, for strength and intelligence were the last features you wanted in a transient.

Hilin had to die, of course. His flayed corpse would be displayed before the shrine of the Elder, as a warning to future generations. But Rusel didn’t have the courage to watch it done. He remembered the man in the electric-blue skinsuit: he always had been a coward, he thought.

As he returned to his Cloister, he looked back once more. ‘And clean up this damn mess,’ he said.

He knew it would take a long time, even on his timescales, before he managed to forget the contemptuous defiance on Hilin’s young face. But Hilin went into the dark like all his transient ancestors, and soon his siblings and nieces and nephews and everybody who looked remotely like him went too, gone, all gone into the sink of time, and soon only Rusel was left alive to remember the rebellion.

Rusel would never leave the Cloister again.

VIII

Some time after that, there was a decimating plague.

It was brought about by a combination of factors: a slow unmonitored build-up of irritants and allergens in the Ship’s environment, and then the sudden emergence of a latent virus in a population already weakened. It was a multiple accident, impossible for the pharaoh designers of the Ship to plan away, for all their ingenuity. But given enough time - more than five thousand years now - such low-probability events inevitably occurred.

The surviving population crashed to the threshold of viability. For a few decades Rusel was forced to intervene, through booming commands, to ensure that the Ship was maintained at a base level, and that genetic-health protocols were observed and breeding matches planned even more carefully than usually.

The low numbers brought benefits, though. The Ship’s systems were now producing a large surplus of supplies, and there was no possibility of any more water empires. Rusel considered, in his glacial way, establishing a final population at a lower level than before.

It intrigued him that the occurrence of the low-probability plague mirrored the restructuring of his own mental processes. The day-to-day affairs of the Ship, and the clattering of the transient generations, barely distracted him now. Instead he became aware of slower pulses, deeper rhythms far beneath any transient’s horizon of awareness.

His perception of risk changed. His endless analysis of the Ship’s systems uncovered obscure failure modes: certain parameter combinations that could disrupt the governing software, interacting failures among the nano-machines that still laboured over the Ship’s fabric inside and out. Such failures were highly unlikely; he estimated the Ship might suffer significant damage once every ten thousand years or so. On Earth, whole civilisations had risen and fallen with greater alacrity than that. But he had to plan for such things, to prepare the Ship’s defences and recovery strategies. The plague, after all, was just such a low-risk event, but given enough time it had come about.

The transients’ behaviour, meanwhile, adjusted on its own timescales.

Once every decade or so the inhabitants of Diluc’s corridor-village would approach the shrine of the Elder, where the flickering Virtual still showed. One of them would dress up in a long robe and march behind a walking frame with exaggerated slowness, while the rest cowered. And then they would fall on a manikin and tear it to pieces. Rusel had watched such displays several times before he had realised what was going on: it was, of course, a ritualised re-enactment of his own last manifestation, the hobbling leader himself, the manikin poor overbright Hilin. Sometimes the bit of theatre would culminate in the flaying of a living human, which they must imagine he demanded; when such savage generations arose, Rusel would avert his cold gaze.

Meanwhile, in the village in which Hilin’s doomed lover Sale had been born, the local transients were trying another tactic to win his favour. Perhaps it was another outcome of Hilin’s clever exploits, or perhaps it had been inherent in the situation all along.

Girls, elfin girls with dark elusive eyes: as the generations ticked by, he seemed to see more of them running in the corridors, making eyes at muscular wall-scrubbing boys, dandling children on their knees. They were like cartoon versions of Lora: tall Loras and short, thin Loras and fat, happy Loras and sad.

It was selective breeding, if presumably unconscious, people turning themselves into replicas of the images in the Virtual. They were appealing directly to his own cold heart: if the Elder loved this woman so much, then choose a wife that looks like her, if only a little, and hope to have daughters with her delicate looks, and so win favour.

Rusel was simultaneously touched, and appalled. But he did not interfere. They could do what they liked, he told himself, as long as they got their jobs done.

Meanwhile in the old amphitheatre, on the other side of the barricade he had erected, the Autarchs and their long-lived families had not died out as Rusel had expected - indeed hoped. They had lived on. And as they inbred ferociously, their lives were stretched out longer and longer.

Again this made sense in terms of their heredity, he thought. In their cordoned-off compartment there was simply no room to expand their population. So the genes’ best bet of propagating themselves into the future, always their only objective, was to stretch out the lives of their carriers. Adults in there now lived for centuries, and for the vanishingly few children born, childhood lasted decades.

Rusel found these creatures, with their blank eyes and wizened-faced children, peculiarly disturbing. On the other hand, he still couldn’t bring himself to kill them off. Perhaps in them he saw a distorted reflection of himself.

There was one constant throughout the Ship. On both sides of the barrier the transients were clearly getting dumber.

As generations passed - and by now, for fear of repeating Hilin’s fate, potential mates were repelled by any signs of higher-than-average intelligence - it was obvious that the transients were breeding themselves into stupidity. If anything the Autarchs’ environment was less stimulating than that of their cousins in the rest of the Ship, and despite their slower generational cycle they were shedding their unnecessary intelligence with even more enthusiasm, perhaps a response to sheer boredom.

The transients kept the Ship working, however, and in their increasingly brutish liaisons followed the genetic-health mandates scrupulously. This puzzled Rusel: surely by now they could have no real understanding of why they were doing these peculiar things.

But he observed that when it came time to attract a mate the most vigorous deck-swabbers and cousin-deniers stood out from the crowd. It made sense: after all, a propensity to please the undeniable reality of the Elder was a survival characteristic, and therefore worth displaying if you had it, and worth preserving in your children’s heredity. He filed away such observations and insights.

By now, nothing that happened inside the Ship’s hull interested him as much as what happened outside.

He was thoroughly wired into the Ship, its electromagnetic and other equipment taking the place of his own failed biological senses. He cruised with it through the intergalactic gulf, feeling the tingle of dark-matter particles as they were swept into the Ship’s gut, sensing the subtle caress of magnetic fields. It fascinated him to follow the million-year turning of the Galaxy, whose brilliant face continued to open up behind the fleeing Ship. Even the space between the galaxies was much more interesting than he had ever imagined. It wasn’t a void at all. There was structure here, he saw, a complex webbing of the dark stuff that spanned the universe, a webbing in which galaxies were trapped like glowing flies. He learned to follow the currents and reefs of the dark matter which the Ship’s gravitational maw greedily devoured.

He was alone with the galaxies, then, and with his own austere mind.

Once, just once, as he drifted in the dark, he heard a strange signal. It was cold and clear, like the peal of a trumpet, far off in the echoing intergalactic night. It wasn’t human at all.

He listened for a thousand years. He never heard it again.

IX

Andres came to him. He could see her face clearly, that worn-smooth expressionless skin. The rest of her body was a blur, a suggestion.

‘Leave me alone, you nagging old witch,’ he grumbled.

‘Believe me, that would be my choice,’ said Andres fervently. ‘But there’s a problem, Rusel. And you need to come out of your damn shell and sort it out.’

He longed for her to leave him, but he knew that wasn’t an option. In a corner of his frayed mind he knew that this Virtual projection of his last companion, a synthesis of his own reflection and the Ship’s systems, was an alarm, activated only when absolutely necessary.

‘What kind of problem?’

‘With the transients. What else? You need to take a look.’

‘I don’t want to. It hurts.’

‘I know it hurts. But it’s your duty.’

Duty? Had she said that, or had he? Was he awake, or dreaming? With time, everything blurred, every category, every boundary.

He was far beyond biology now, of course. It was only technology that kept him alive. With time, the Ship had infiltrated its treatments and systems deeper into the shell of what had been his body. It was as if he had become just another of the Ship’s systems, like the air scrubbers or the water purifiers, just as old and balky, and just as much in need of endless tender loving care.

The decay of his central nervous system had proceeded so far that he wasn’t sure if it returned any signals to the hardening nugget of his brain; he wasn’t sure if he perceived the outside universe unfiltered at all. And even the walls of his consciousness were wearing away. He thought of his mind as a dark hall filled with drifting forms, like zero-gravity sculptures. These were his memories - or perhaps memories of memories, recycled, reiterated, edited and processed.

And he was here, a pinpoint awareness that flitted and flew between the drifting reefs of memory. At times, as he sailed through the abstraction of emptiness, free of memory or anticipation, indeed free of any conscious thought save only a primal sense of self, he felt oddly free - light, unburdened, even young again. But whenever that innocent point settled into the dark tangle of a memory reef, the guilt came back, a deep muddy shame whose origins he had half-forgotten, and whose resolution he could no longer imagine.

He wasn’t alone, however, in this cavernous awareness. Sometimes voices called from the dark. Sometimes there were even faces, their features softened, their ages indeterminate. Here was Diluc, his brother, or Andres, or Ruul or Selur or one of the others. He knew they were all long dead save for him, who lived on and on. He had vague memories of setting up some of these Virtual personas as therapy for himself, or as ways for the Ship to attract his attention - Lethe, even as company. But by now he wasn’t sure what was Virtual and what was a dream, a schizoid fantasy of his rickety mind.

Lora was never there, however.

And Andres, the cold pharaoh who had become his longest-enduring companion, was his most persistent visitant.

‘Nobody ever said this would be easy, Rusel.’

‘You said that before.’

‘Yes. And I’ll keep on saying it until we get to Canis Major.’

‘Canis Major? . . .’ The destination. He’d forgotten about it again, forgotten that an end to all this even as a theoretical possibility might exist. The trouble was, thinking about such things as a beginning and an end made him aware of time, and that was always a mistake.

How long? The answer came to him like a whisper. Round numbers? Twenty thousand years gone. Twenty thousand years. It was ridiculous, of course.

‘Rusel,’ Andres snapped. ‘You need to focus.’

‘You’re not even Andres,’ he grumbled.

Her mouth was round with mock horror. ‘Really? Oh, no! What an existential disaster for me.’ She glared. ‘Just do it, Rus.’

So, reluctantly, he gathered his scattered concentration, and sent his viewpoint out into the body of the Ship. He was faintly aware of Andres riding alongside him, a ghost at his shoulder.

He found the place he still thought of as Diluc’s village. The framework of corridors and cabins hadn’t changed, of course; it was impossible that it should. But even the non-permanent partitions that had once been built up and torn down by each successive generation of transients had been left unmoved since the last time he was here. Building things wasn’t what people did any more.

He wandered into the little suite of rooms that had once been Diluc’s home. There was no furniture. Nests were crammed into each corner of the room, disorderly heaps of cloth and polymer scraps. He had seen the transients take standard-issue clothing from the Ship’s recycler systems and immediately start tearing it up with hands or teeth to make their coarse bedding. There was a strong stink of piss and shit, of blood and milk, sweat and sex, the most basic human biology. But the crew remained scrupulously clean. Every few days all this stuff would be swept up and carted off to the recycler bins.

This was the way people lived now. They nested in starship cabins.

Outside, the walls and partitions were clean, gleaming and sterile, as was every surface he could see, the floor and ceiling. One partition had been rubbed until it was worn so thin the light shone through it: another couple of generations and it would wear away altogether, he thought. The crew still kept up their basic duties; that had remained, while so much else had vanished.

But these latter transients were not crewing the Ship as his own generation once had, for conscious purposes. They were doing it for deeper reasons.

The transients competed in how well they did their chores in order to attract mates, and these selection pressures had, given time, sculpted the population. By now the transients were maintaining a starship’s systems as bees had once danced, stags had locked antlers, and peacocks had spread their useless tails: they were doing it for sex, and the chance to procreate. As mind receded, Rusel thought, biology had taken over.

As long as they were doing it in the first place, Rusel didn’t care. Besides, it worked in maintaining the ship. Sexual drivers seemed very effective in locking in behaviour with the precision required to keep the Ship’s systems functioning: you could fix a ceiling ventilation grille with a show-off flourish or not, but you had to do it exactly correctly to impress the opposite sex, even if you didn’t understand what it was for. Even when mind was gone, you had to do it right.

He heard weeping, not far away.

He let his viewpoint drift along the corridor, following the sound. He turned a corner, and came on the villagers.

There were perhaps twenty-five of them, adults and children. They were all naked, of course; nobody had worn clothes for millennia. Some of them had infants in their arms or on their backs. Squatting in the corridor, they huddled around a central figure, the woman who was doing the weeping. She was cradling something, a bloody scrap. The others reached out and stroked her back and scalp; some of them were weeping too, Rusel saw.

He said, ‘Their empathy is obvious.’

‘Yes. They’ve lost so much else, but not that.’

Suddenly their heads turned, all of them save the weeping woman, faces swivelling like antennae. Something had disturbed them - perhaps the tiny hovering drone that was Rusel’s physical manifestation. Their brows were low, but their faces were still human, with straight noses and delicate chins. It was like a flower bed of faces, Rusel thought, turned up to his light. But their mouths were pulled back in fear-grins.

And every one of them looked like Lora, more or less, with that delicate, elfin face, even something of her elusive eyes. Of course they did: the blind filter of natural selection, operating for generations on this hapless stock, had long determined that though mind was no longer necessary, to look this way might soften the heart of the wizened creature who ruled the world.

The strange tableau of upturned Lora-faces lasted only a moment. Then the transients took flight. They poured away down the corridor, running, knuckle-walking, bounding off the walls and ceiling.

Andres growled, ‘I’ll swear they get more like chimps with every generation.’

In a few seconds they had gone, all save the weeping woman.

Rusel allowed his viewpoint to swim towards the woman. He moved cautiously, not wishing to alarm her. She was young - twenty, twenty-one? It was increasingly hard to tell the age of these transients; they seemed to reach puberty later each generation. This girl had clearly passed her menarche - in fact she had given birth, and recently: her belly was slack, her breasts heavy with milk. But her chest was smeared with blood, shocking bright crimson in the drab, worn background of the corridor. And the thing she was cradling was no child.

‘Lethe,’ said Rusel. ‘It’s a hand. A child’s hand. I think I’m going to throw up.’

‘You no longer have the equipment to throw up. Take a closer look.’

A white stump of bone stuck out of a bloody mass of flesh. The hand had been severed at the wrist. And two tiny fingers had been almost stripped of flesh, ligament and muscle, leaving only tiny bones.

‘That wrist,’ Andres said pitilessly, ‘has been bitten through. By teeth, Rusel. And teeth have been at work on those fingers as well. Think about it. With a bit of practice, you could take one of those little morsels between your incisors and just strip off the flesh and muscle—’

‘Shut up! Lethe, Andres, I can see for myself. We always avoided cannibalism. I thought we beat that into their shrinking skulls hard enough.’

‘So we did. But I don’t think this is cannibalism - or rather, whatever did this wasn’t her kind.’

Rusel elevated the viewpoint and cast around. He saw a trail of blood leading away from the woman, smeared along the walls and floor, quite unmistakable, as if something had been dragged away.

Andres said, ‘I think our transients suddenly have a predator.’

‘Not so suddenly,’ Rusel said. A part of his scattered consciousness was checking over the Ship’s logs, long ignored. This kind of incident had been going on for a couple of centuries. ‘It’s been rare before, once or twice a generation. Mostly it was the old who were taken, or the very young - vulnerable, dispensable, or replaceable. But now they seem to be upping the rate.’

‘And making a dent in the transients’ numbers.’

‘Yes. You were right to bring me here.’ This had to be resolved. But to do it, he thought with a deepening dread, he was going to have to confront a horror he had shut out of his awareness for millennia.

‘I’m here with you,’ Andres said gently.

‘No, you’re not,’ he snapped. ‘But I have to deal with this anyhow.’

‘Yes, you do.’

His viewpoint followed the bloody trail as it wound through the corridor-villages of the transients. Broken in places, the trail slinked through shadows or through holes worn in the walls. It was the furtive trail of a hunter, he thought.

At last Rusel came to the bulkhead that cut the Ship in two, marking the limit of his transients’ domain. He had long put out of his mind what lay beyond this wall: in fact, if he could have cut away the Ship’s aft compartment and let the whole mess float off into space he would long ago have done so.

But there was a hole in the bulkhead, just wide enough to admit a slim body.

The bulkhead was a composite of metal and polymer, extremely tough, and a metre thick; the hole was a neat tunnel, not regular but smooth-walled, drilled right through. ‘I can’t believe they have tools,’ he said. ‘So how did they get through?’

‘Teeth,’ Andres said. ‘Teeth and nails - and time, of which they have plenty. Remember what you’re dealing with. Even if the bulkhead was made of diamond they’d have got through eventually.’

‘I hoped they were dead.’

‘Hope! Wishful thinking! That always was your weakness, Rusel. I always said you should have killed them off in the first place. They’re just a drain on the Ship’s resources.’

‘I’m no killer.’

‘Yes, you are—’

‘And they are human, no less than the transients.’

‘No, they’re not. And now, it seems, they are eating our transients.’

His viewpoint drifted before the hole in the wall. Andres seemed to sense his dread; she didn’t say anything.

He passed through the barrier.

He emerged in the upended chamber he still thought of as the amphitheatre, right at the base of the Ship. This was a big, bare volume, a cylinder set on its side. After the spin-up it had been used to pursue larger-scale reconstruction projects necessary to prepare the Ship for its long intergalactic voyage, and mounted on its floor and walls were the relics of heavy engineering, long abandoned: gantries, platforms of metal, immense low-gravity cranes like vast skeletons. Globe lights hovered everywhere, casting a yellow-white light complex with shadows. It was an oddly magnificent sight, Rusel thought, and it stirred memories of brighter, more purposeful days. On the wall of the chamber, which had been its floor, he could even make out the brackets which had held the acceleration couches on launch day.

Now, every exposed surface was corroded. Nothing moved. And that upturned floor, which Andres had turned transparent a mere year after the launch, was caked by what looked like rock. It was a hardened pack of faeces and cloth scraps and dirt, a wall of shit to block out the Galaxy.

At first, in this jungle of engineering, he couldn’t make out anything living. Then, as he allowed the worn-out ambience of the place to wash over him, he learned to see.

They were like shadows, he thought, slim, upright shadows that flitted through the gantries, furtive, cautious. At times they looked human - clearly upright, bipedal, purposeful - though their limbs were spindly, their bellies distended. But then they would collapse to all fours and lope away with a bent gait, and that impression of humanity vanished. They didn’t seem to be wearing clothes, any more than the transients did. But unlike the transients their bodies were coated with a kind of thick hair, dark brown, a fur.

Here and there hovering drones trailed the shambling creatures, carrying food and water. The creatures ignored these emissaries of the Ship that kept them alive.

Andres said grimly, ‘I know you haven’t wanted to think about these relics, Rusel. But the Ship has watched over them. They are provided with food, of course. Clothing, blankets and the like - they rip all that up to serve as nesting material, like the transients. They won’t go to the supply hoppers as the transients will; drones have to bring them the stuff they need, and take out their waste. But they’re really quite passive. They don’t mind the drones, even when the drones clean them, or tend to wounds or sicknesses. They are used to being cared for by machines.’

‘But what do they do all day?’

Andres laughed. ‘Why, nothing. Nothing but eat the food we give them. Climb around the gantries a little, perhaps.’

‘They must have some spark of curiosity, of awareness. The transients do! They’re people.’

‘Their ancestors used to be. Now they’re quite mindless . . . There. Look. They are gathering at one of their feeding places. Perhaps we’ll be able to see what they do.’

The feeding site was a shallow depression, worn into a floor of steel. Its base was smeared green and brown. A drone had delivered a cache of food to the centre of the pit, a pile of spheres and cylinders and discs, all sized for human hands, all brightly coloured.

From around the amphitheatre the animals came walking, loping, moving with the slow clumsiness of low gravity - and yet with an exaggerated care, Rusel thought, as if they were very fragile, very old. They gathered around the food pile. But they did not reach for the food; they just slumped down on the ground, as if exhausted.

Now smaller creatures emerged from the forest of gantries. They moved nervously, but just as cautiously as the larger forms. They must be children, Rusel thought, but they moved with no spontaneity or energy. They were like little old people themselves. There were far fewer children than adults, just a handful among perhaps fifty individuals.

It was the children who went to the food pile, broke off pieces of the brightly coloured fodder, and carried it to the adults. The adults greeted this service with indifference, or at best a snarl, a light blow on the head or shoulder. Each child servant went doggedly back to the pile for more.

‘They’re not particularly hygienic,’ Rusel observed.

‘No. But they don’t have to be. Compared to the transients they have much tougher immune systems. And the Ship’s systems keep the place roughly in order.’

Rusel said, ‘Why don’t the adults get the food themselves? It would be quicker.’

Andres shrugged. ‘This is their way. And it is their way to eat another sort of food, too.’

At the very centre of the depression was a broad scar stained a deep crimson brown, littered with lumpy white shapes.

‘That’s blood,’ Rusel said, wondering. ‘Dried blood. And those white things—’

‘Bones,’ said Andres evenly. Rusel thought she seemed oddly excited, stirred by the degraded spectacle before her. ‘But there’s too much debris here to be accounted for by their occasional raids into transient country.’

Rusel shuddered. ‘So they eat each other too.’

‘No. Not quite. The old eat the young; mothers eat their children. It is their way.’

‘Oh, Lethe . . .’ Andres was right; Rusel couldn’t throw up. But he was aware of his body, cradled by the concerned Ship, thrashing feebly in distress.

Andres said dispassionately, ‘I don’t understand your reaction.’

‘I didn’t know—’

‘You should have thought it through - thought through the consequences of your decision to let these creatures live.’

‘You are a monster, Andres.’

She laughed without humour.

Of course he knew what these animals were. They were the Autarchs - or the distant descendants of the long-lived, inbred clan who had once ruled over the transients. Over nearly twenty thousand years selection pressure had worked relentlessly, and the gene complex that had given them their advantage over the transients in the first place - genes for longevity, a propensity injected into the human genome by the Qax - had found full expression. And meanwhile, in the sterile nurture of this place, they had had even less reason to waste precious energy on large brains.

As time had passed they had lived longer and longer, but thought less and less. Now these Autarchs were all but immortal, and all but mindless.

‘They’re actually rather fascinating,’ Andres said cheerfully. ‘I’ve been trying to understand their ecology, if you will.’

‘Ecology? Then maybe you can explain how it can benefit a creature to treat its children so. Those young seem to be farmed. Life is about the preservation of genes: even in this artificial little world of ours, that remains true. So how does eating your kids help achieve that? . . . Ah.’ He gazed at the hairy creatures before him. ‘But these Autarchs are not mortal.’

‘Exactly. They lost their minds, but they stayed immortal. And when mind had gone, natural selection worked with what it found.’

Even for these strange creatures, the interests of the genes were paramount. But now a new strategy had to be worked out. It had been foreshadowed in the lives of the first Autarchs. There was no room to spread the genes by expanding the population - but if individuals could become effectively immortal, the genes could survive through them.

Andres said, ‘But simple longevity wasn’t enough. Even the longest-lived will die through some accident eventually. The genes themselves can be damaged, through radiation exposure for instance. Copying is safer! For their own preservation the genes need to see some children produced, and for some, the smartest and strongest, to survive.

‘But, you see, living space is restricted here. The parents must compete for space against their own children. They don’t care about the children. They use them as workers - or even, when there’s an excess, as a cannibalistic resource . . . But there are always one or two children who fight their way through to adulthood, enough to keep the stock numbers up. In a way the pressure from the adults is a mechanism to ensure that only the smartest and strongest of the kids survive. It’s a mixed strategy.’

‘From the genes’ point of view it’s a redundancy mechanism, ‘ Rusel said. ‘That’s the way an engineer would put it. The children are just a fail-safe.’

‘Precisely,’ Andres said.

It was biology, evolution: the destiny of the Mayflower had come down to this.

Rusel had brooded on the fate of his charges, and had studied how time had always shaped human history. And he had decided it was all a question of timescales.

The conscious purpose of the Ship had sustained its crew’s focus for a century or so, until the first couple of generations, and the direct memory of Port Sol, had vanished into the past.

Millennia, though, were the timescale of historical epochs on Earth, over which empires rose and fell. His studies suggested that to sustain a purpose over such periods required the engagement of a deeper level of the human psyche: the idea of Rome, say, or a devotion to Christ. If the first century of the voyage had been an arena for the conscious, over longer periods the unconscious took over. Rusel had seen it himself, as the transients had become devoted to the idea of the Ship and its mission, as embodied by his own Virtual. Even Hilin’s rebellion had been an expression of that cult of ideas. Call it mysticism: whatever, it worked over epochs of thousands of years.

That far, he believed, Andres and the other pharaohs had been able to foresee and plan for. But beyond that even they hadn’t been able to imagine; Rusel had sailed uncharted waters.

And as time heaped up into tens of millennia, he had crossed a span of time comparable to the rise and fall, not just of empires, but of whole species. A continuity of the kind that kept the transients cleaning the walls over such periods could only come about, not through even the deepest layers of mind, but through much more basic biological drivers, like sexual selection: the transients cleaned for sex, not for any reason to do with the Ship’s goals, for they could no longer comprehend such abstractions. And meanwhile natural selection had shaped his cradled populations, of transients and Autarchs alike.

Sometimes he felt queasy, perhaps even guilty, at the distorted fate to which generation upon generation had been subjected, all for the sake of a long-dead pharaoh and her selfish, hubristic dream. But individual transients were soon gone, their tiny motes of joy or pain soon vanishing into the dark. Their very brevity was comforting.

Of course, if biology was replacing even the deepest layers of mind as the shaping element in the mission’s destiny, Rusel’s own role became still more important, as the only surviving element of continuity, indeed of consciousness.

Whatever, there was no going back, for any of them.

Andres was still watching the Autarchs. ‘You know, immortality, the defeat of death, is one of mankind’s oldest dreams, But immortality doesn’t make you a god. You have immortality, Rusel, but, save for your crutch the Ship, you have no power. And these - animals - have immortality, but nothing else.’

‘It’s monstrous.’

‘Of course! Isn’t life always? But the genes don’t care. And in the Autarchs’ mindless capering, you can see the ultimate logic of immortality: for an immortal, to survive, must in the end eat her own children.’

But everybody on this Ship was a child of this monstrous mother, Rusel thought, whose twisted longings had impelled this mission in the first place. ‘Is that some kind of confession, pharaoh?’

Andres didn’t reply. Perhaps she couldn’t. After all this wasn’t Andres but a Virtual, a software-generated comfort for Rusel’s fading consciousness, at the limit of its programming. And any guilt he saw in her could only be a reflection of himself.

With an effort of will he dismissed her.

One of the adults, a male, sat up, scratched his chest, and loped to the centre of the feeding pit. The young fled at his approach. The male scattered the last bits of primary-colour food, and picked up something small and white. It was a skull, Rusel saw, the skull of a child. The adult crushed it, dropped the fragments, and wandered off, aimless, immortal, mindless.

Rusel withdrew, and sealed up the gnawed-through bulkhead. After that he set up a new barrier spanning the Ship parallel to the bulkhead, and opened up the thin slice of the vessel between the walls to intergalactic vacuum, so that nothing could come through that barrier. And he never again gave any thought to what lay on the other side.

X

Twenty-five thousand years after the end of his world, Rusel heard that he was to be saved.

‘Rusel. Rusel . . .’

Rusel wanted the voices to go away. He didn’t need voices now - not Diluc’s, not even Andres’s.

He had no body, no belly, no heart; he had no need of people at all. His memories were scattered in emptiness, like the faint smudges that were the remote galaxies all around the Ship. And like the Ship he forged on into the future, steadily, pointlessly, his life empty of meaning. The last thing he wanted was voices.

But they wouldn’t go away. With deep reluctance, he forced his scattered attention to gather.

The voices were coming from Diluc’s corridor-village. Vaguely, he saw people there, near a door - the door where he had once been barrelled into by little Tomi, he remembered, in a shard of bright warm memory blown from the past - two people, by that same door.

People standing upright. People wearing clothes.

They were not transients. And they were calling his name into the air. With a mighty effort he pulled himself to full awareness.

They stood side by side, a man and a woman - both young, in their twenties, perhaps. They wore smart orange uniforms and boots. The man was clean-shaven, and the woman bore a baby in her arms.

Transients had clustered around them. Naked, pale, eyes wide with curiosity, they squatted on their haunches and reached up with their long arms to the smiling newcomers. Some of them were scrubbing frantically at the floor and walls, teeth bared in rictus grins. They were trying to impress the newcomers with their prowess at cleaning, the only way they knew how. The woman allowed the transients to stroke her child. But she watched them with hard eyes and a fixed smile. And the man’s hand was never far away from the weapon at his belt.

It took Rusel a great deal of effort to find the circuits that would allow him to speak. He said, ‘Rusel. I am Rusel.’

As the disembodied voice boomed out of the air the man and woman looked up, startled, and the transients cowered. The newcomers looked at each other with delight. ‘It’s true,’ said the man. ‘It really is the Mayflower!’ A translation whispered to Rusel.

The woman scoffed. ‘Of course it’s the Mayflower. What else could it be?’

Rusel said, ‘Who are you?’

The man’s name was Pirius, the woman’s Torec.

‘Are we at Canis Major?’

‘No,’ Pirius said gently.

These two had come from the home Galaxy - from Sol system itself, they said. They had come in a faster-than-light ship; it had overtaken the Mayflower’s painful crawl in a few weeks. ‘You have come thirteen thousand light years from Port Sol,’ Pirius said. ‘And it took you more than twenty-five thousand years. It is a record for a generation starship! An astonishing feat.’

Thirteen thousand light years? Even now, the Ship had come only halfway to its intended destination.

Torec cupped the face of a transient girl in her hand - Lora’s face. ‘And,’ Torec said, ‘we came to find you.’

‘Yes,’ said Pirius, smiling. ‘And your floating museum!’

Rusel thought that over. ‘Then mankind lives on?’

Oh, yes, Pirius told him. The mighty Expansion from which the Mayflower’s crew had fled had burned its way right across the Galaxy. It had been an age of war; trillions had gone into the dark. But mankind had endured.

‘And we won!’ Pirius said brightly. Pirius and Torec themselves had been involved in some kind of exotic combat to win the centre of the Galaxy. ‘It’s a human Galaxy now, Rusel.’

‘Human? But how are you still human?’

They seemed to understand the question. ‘We were at war,’ Pirius said. ‘We couldn’t afford to evolve.’

‘The Coalition—’

‘Fallen. Vanished. Gone. They can’t harm you now.’

‘And my crew?’

‘We will take them home. There are places where they can be cared for. But, ah—’

Torec said, ‘But the Ship itself is too big to turn around. Too much mass-energy. I’m not sure we can bring you back.’

Once he had seen himself, a stiff ageless man, through the eyes of Diluc’s great-grandson Poro, through the eyes of a child. Now, just for an instant, he saw himself through the eyes of Pirius and Torec. A wizened, charred thing suspended in a webbing of wires and tubes.

That didn’t matter, of course. ‘Have I fulfilled my mission?’

‘Yes,’ Pirius said gently. ‘You fulfilled it very well.’

He wasn’t aware of Pirius and Torec shepherding the transients and Autarchs out of the Ship and into their own absurdly small craft. He wasn’t aware of Pirius’s farewell call as they shot away, back towards the bright lights of the human Galaxy, leaving him alone. He was only aware of the Ship now, the patient, stolid Ship.

The Ship - and one face, revealed to him at last: an elfin face, with distracted eyes, He didn’t know if she was a gift of Pirius or even Andres, if she was outside his own head or inside. None of that seemed to matter when at last she smiled for him, and he felt the easing of a tension twenty-five millennia old, the dissolving of a clot of ancient guilt.

The Ship forged on into the endless dark, its corridors as clean and bright and empty as his thoughts.

I knew Andres. I knew about the five Ships that sailed from Port Sol. I always wondered what happened to her.

Some of the Ships sailed on to even more exotic fates than her Mayflower’s. But that’s another story.

The conquest of the Galaxy was perhaps humanity’s finest hour. The ministers, generals and Commissaries at the heart of the Coalition looked back on the immense achievement of their ideological government with, perhaps, justifiable pride.

But it was an irony that as soon as the victory was won, the Coalition lost its purpose, and its control.

And it was an irony, I thought, that a crude faith of child soldiers, outlawed by the Coalition, should not only outlive the Coalition itself but even shape the history that followed its demise.

Table of Contents

REALITY DUST

RIDING THE ROCK

I

II

III

IV

MAYFLOWER II

I

II

III

IV

V

VI

VII

VIII

IX

X