Phase Space

The first time Kate had come here, to his son's home, Malenfant had shown her an image of a planet: blue, streaked with white cloud.

Kate's heart had thumped. 'Earth?'

He shook his head. 'And not Pluto either. This is a live image of Neptune. Almost as far out as Pluto. A strange blue world, blue as Earth, on the edge of interstellar space…'

Saranne said uneasily, 'What's wrong with it?'

'Not Neptune itself. Triton, its moon. Look.' He pointed to a blurred patch of light, close to Neptune's ghostly limb. When he tapped the wall, the patch moved, quite suddenly. Another tap, another move. Kate couldn't see any pattern to the moves, as if the moon was no longer following a regular orbit.

‘I don't understand,' she said.

'Triton has started to… flicker. It hops around its orbit - or adopts another orbit entirely - or sometimes it vanishes, or is replaced by a ring system.' He scratched his bald pate. 'According to Cornelius, Triton was an oddity - circling Neptune backwards - probably created in some ancient collision event.'

'Even odder now,' Mike said dryly.

'Cornelius says that all these images - the multiple moons, the rings - are all possibilities, alternate outcomes of how that ancient collision might have come about. As if other realities are folding down into our own. Other realities, from out there in phase space.' He searched their faces, seeking understanding.

Kate took a breath. Neptune: a long way away, out in the dark, where the planets are cloudy spheres, and the sun's light is weak and rectilinear. But out there, she thought, something strange is stirring: something with awesome powers indeed, beyond human comprehension.

‘I wonder,' Malenfant said, 'if we are out there somewhere. Versions of us and those we love, with different destinies. Lost in phase space.'

Sheena 5

Sheena didn't mean it to happen.

Of course not; she knew the requirements of the mission as well as anyone, as well as Dan himself. She had her duty to NASA. She understood that.

But it felt so right.

It came after the kill.

The night was over. The sun, a fat ball of light, was already glimmering above the water surface.

The squid emerged from the grasses and corals where they had been feeding. Shoals formed in small groups and clusters, eventually combining into a community a hundred strong.

Court me. Court me.

See my weapons!

I am strong and fierce.

Stay away! Stay away! She is mine!…

It was the ancient cephalopod language, a language of complex skin patterns, body posture, texture, words of sex and danger and food; and Sheena shoaled and sang with joy.

… But there was a shadow on the water.

The sentinels immediately adopted concealment or bluff postures, blaring lies at the approaching predator.

Sheena knew that there would be no true predators here. The shadow could only be a watching NASA machine.

The dark shape lingered close, just as a true barracuda would, before diving into the shoal, seeking to break it up.

A strong male broke free. He spread his eight arms, raised his two long tentacles, and his green binocular eyes fixed on the fake

barracuda. Confusing patterns of light and shade pulsed across his hide. Look at me. 1 am large and fierce. I can kill you. Slowly, cautiously, the male drifted towards the barracuda, coming to within a mantle length.

At the last moment the barracuda turned, sluggishly.

But it was too late.

The male's two long tentacles whipped out, and their club-like pads of suckers pounded against the barracuda hide, sticking there. Then the male wrapped his eight strong arms around the barracuda's body, his pattern changing to an exultant uniform darkening. And he stabbed at the barracuda's skin with his beak, seeking meat.

And meat there was, what looked like fish fragments to Sheena, booty planted there by Dan.

The squid descended, lashing their tentacles around the stricken prey. Sheena joined in, cool water surging through her mantle, relishing the primordial power of this kill despite its artifice.

… That was when it happened.

As she clambered stiffly down through the airlock into the habitat, the smell of air freshener overwhelmed Maura Delia.

'Ms Delia, welcome to Oceanlab,' Dan Ystebo said. Ystebo, marine biologist, was fat, breathy, intense, thirtyish, with Coke-bottle glasses and a mop of unlikely red hair, a typical geek scientist type.

Maura found a seat before a bank of controls. The seat was just a canvas frame, much repaired with duct tape. The working area of this hab was a small, cramped sphere, its walls encrusted with equipment. A sonar beacon pinged softly, like a pulse.

The sense of confinement, the feel of the weight of water above her head, was overwhelming.

She leaned forward, peering into small windows. Sunlight shafted through empty grey water. She saw a school of squid, jetting through the water in complex patterns.

'Which one is Sheena 5?'

Dan pointed to a softscreen pasted over a scuffed hull section.

The streamlined, torpedo-shaped body was a rich burnt-orange, mottled black. Wing-like fins rippled elegantly alongside the body.

The Space Squid, Maura thought. The only mollusc on NASA's payroll.

'Sepioteuthis sepioidea,' Dan said. 'The Caribbean reef squid.

About as long as your arm. Squid, all cephalopods in fact, belong to the phylum Mollusca. But in the squid the mollusc foot has evolved into the funnel, here, leading into the mantle, and the arms and tentacles here. The mantle cavity contains the viscera and gills. Sheena can use the water passing through her mantle cavity for jet propulsion -'

'How do you know that's her?'

Dan pointed again. 'See the swelling between the eyes, around the oesophagus?'

'That's her enhanced brain?'

'A squid's neural layout isn't like ours. Sheena has two nerve cords running like rail tracks the length of her body, studded with pairs of ganglia. The forward ganglia pair is expanded into a mass of lobes. We gen-enged Sheena and her grandmothers to -'

'To make a smart squid.'

'Ms Delia, squid are smart anyway. They evolved - a long time ago, during the Jurassic - in competition with the fish. They have senses based on light, scent, taste, touch, sound - including infrasound - gravity, acceleration, perhaps even an electric sense. Sheena can control her skin patterns consciously. She can make bands, bars, circles, annuli, dots. She can even animate the display.'

'And these patterns are signals?'

'Not just the skin patterns: skin texture, body posture. There may be electric or sonic components too; we can't be sure.'

'And what do they use this marvellous signalling for?'

'We aren't sure. They don't hunt cooperatively. And they live only a couple of years, mating only once or twice.' Dan scratched his beard. 'But we've been able to isolate a number of primal linguistic components which combine in a primitive grammar. Even in unenhanced squid. But the language seems to be closed. It's about nothing but food, sex and danger. It's like the dance of the bee.'

'Unlike human languages.'

'Yes. So we opened up Sheena's language for her. In the process we were able to prove that the areas of the brain responsible for learning are the vertical and superior frontal lobes that lie above the oesophagus.'

'How did you prove that?'

Dan blinked. 'By cutting away parts of squid brains.' Maura sighed. What great PR if that got broadcast. They studied Sheena. Two forward-looking eyes, blue-green rimmed with orange, peered briefly into the camera.

Alien eyes. Intelligent.

Do we have the right to do this, to meddle with the destiny of other sentient creatures, to further our own goals - when we don't even understand, as Ystebo admits, what the squid use their speech for. What it is they talk about?

How does it feel, to be Sheena?

And could Sheena possibly understand that humans are planning to have her fly a rocket ship to an asteroid?

He came for her: the killer male, one tentacle torn on some loose fragment of metal.

She knew this was wrong. And yet it was irresistible.

She felt a skin pattern flush over her body, a pied mottling, speckled with white spots. Court me.

He swam closer. She could see his far side was a bright uniform silver, a message to the other males: Keep away. She is mine! As he rolled the colours tracked around his body, and she could see the tiny muscles working the pigment sacs on his hide.

And already he was holding out his hectocotylus towards her, the modified arm bearing the clutch of spermatophores at its tip.

Mission Sheena mission. Bootstrap! Mission! NASA! Dan!

But then the animal within her rose, urgent. She opened her mantle to the male.

His hectocotylus reached for her, striking swiftly, and lodged the needle-like spermatophore among the roots of her arms.

Then he withdrew. Already it was over.

… And yet it was not. She could choose whether or not to embrace the spermatophore and place it in her seminal receptacle. She knew she must not.

All around her, the squid's songs pulsed with life, ancient songs that reached back to a time before humans, before whales, before even the fish.

Her life was short: lasting one summer, two at most, a handful of matings. But the songs of light and dance made every squid aware she was part of a continuum that stretched back to those ancient seas; and that her own brief, vibrant life was as insignificant, yet as vital, as a single silver scale on the hide of a fish.

Sheena, with her human-built mind, was the first of all cephalopods to be able to understand this. And yet every squid knew it, on some level that transcended the mind.

But Sheena was no longer part of that continuum.

Even as the male receded, she felt overwhelmed with sadness, loneliness, isolation. Resentment.

She closed her arms over the spermatophore, and drew it inside her.

'I have to go into bat for you on the Hill Monday,' Maura said to Dan. 'I have to put my reputation on the line, to save this project. You're sure, absolutely sure, this is going to work?'

'Absolutely,' Dan said. He spoke with a calm conviction that made her want to believe him. 'Look, the squid are adapted to a zero-gravity environment - unlike us. And Sheena can hunt in three dimensions; she will be able to navigate. If you were going to evolve a creature equipped for space travel, it would be a cephalopod. And she's much cheaper than any robotic equivalent…'

'But,' Maura said heavily, 'we don't have any plans to bring her back.'

He shrugged. 'Even if we had the capability, she's too shortlived. We have plans to deal with the ethical contingencies.' 'That's bullshit.'

Dan looked uncomfortable. But he said, 'We hope the public will accept the arrival of the asteroid in Earth orbit as a memorial to her. A just price. And, Senator, every moment of her life, from the moment she was hatched, Sheena has been oriented to the goal. It's what she lives for. The mission.'

Sombrely Maura watched the squid, Sheena, as she flipped and jetted in formation with her fellows.

We have to do this, she thought. I have to force the funding through, on Monday.

If Sheena succeeded she would deliver, in five years or so, a near-Earth asteroid rich in organics and other volatiles to Earth orbit. Enough to bootstrap, at last, an expansion off the planet. Enough, perhaps, to save mankind.

And, if the gloomier State Department reports about the state of the world were at all accurate, it might be the last chance anybody would get.

But Sheena wouldn't live to see it.

The squid shoal collapsed to a tight school and jetted away, rushing out of sight.

Sheena 5 glided at the heart of the ship, where the water that passed through her mantle, over her gills, was warmest, richest. The core machinery, the assemblage of devices that maintained life here, was a black mass before her, lights winking over its surface.

She found it hard to rest, without the shoal, the mating and learning and endless dances of daylight.

Restless, she swam away from the machinery cluster. As she rose the water flowing through her mantle cooled, the rich oxygen thinning. She sensed the subtle sounds of living things: the smooth rush of fish, the bubbling murmur of the krill on which they browsed, and the hiss of the diatoms and algae which fed them. In Sheena's spacecraft, matter and energy flowed in great loops, sustained by sunlight, regulated by its central machinery as if by a beating heart.

She reached the wall of the ship. It was translucent. If she pushed at it, it pushed back. Grass algae grew on the wall, their long filaments dangling and wafting in the currents.

Beyond the membrane shone a milky, blurred sun - with, near it, a smaller crescent. That, she knew, was the Earth, all its great oceans reduced to a droplet. This craft was scooting around the sun after Earth like a fish swimming after its school.

She let the lazy, whale-like roll of the ship carry her away from the glare of the sun, and she peered into the darkness, where she could see the stars.

She had been trained to recognize many of the stars. She used this knowledge to determine her position in space far more accurately than even Dan could have, from far-off Earth.

But to Sheena the stars were more than navigation beacons. Sheena's eyes had a hundred times the number of receptors of human eyes, and she could see a hundred times as many stars.

To Sheena the universe was crowded with stars, vibrant and alive. The Galaxy was a reef of stars beckoning her to come jet along its length.

But there was only Sheena here to see it. Her sense of loss grew inexorably.

So, swimming in starlight, Sheena cradled her unhatched young, impatiently jetting clouds of ink in the rough shape of a male with bright, mindless eyes.

Maura Delia was involved in all this because - in the year 2030, as the planet's resources dwindled - Earth had become a bear pit.

Take water, for instance.

Humanity was using more than all the fresh water that fell on the planet. Unbelievable. So, all over Asia and elsewhere, water wars were flaring up, and at least one nuke had been lobbed, between India and Pakistan.

America's primary international problem was the small, many-sided war that was flaring in Antarctica, now that the last continent had been 'opened up' to a feeding frenzy of resource-hungry nations - a conflict that constantly threatened to spill out to wider arenas.

And so on.

In Maura's view, all humanity's significant problems came from the world's closure, the lack of a frontier.

Maura Delia had grown up believing in the importance of the frontier. Frontiers were the forcing ground for democracy and inventiveness. In a closed world, science was strangled by patent laws and other protective measures, and technological innovation was restricted to decadent entertainment systems and the machinery of war. It was a vicious circle, of course; only smartness could get humanity out of this trap of closure, but smartness was the very thing that had no opportunity to grow.

America, specifically, was going to hell in a handbasket. Long dwarfed economically by China, now threatened militarily, America had retreated, become risk-averse. The rich cowered inside vast armoured enclaves; the poor lost themselves in VR fantasy worlds; American soldiers flew over the Antarctic battle zones in armoured copters, while the Chinese swarmed over the icebound land they had taken.

And, such were the hangovers from America's dominant days, the US remained the most hated nation on Earth.

The irony was, there were all the resources you could wish for, floating around in the sky: the asteroids, the moons of Jupiter and Saturn, free power from the sun. People had known about this for decades. But after seventy years of spaceflight nobody had come up with a way to get into Earth orbit that was cheap and reliable enough to make those sky mines an economic proposition.

But now this NASA back-room wacko, Dan Ystebo from JPL, had come up with a way to break through the bottleneck, a Space Squid that could divert one of those flying mountains.

Maura didn't care what his own motives were; she only cared

how she could use his proposals to achieve her own goals.

So when Dan invited her to JPL for the rendezvous, she accepted immediately.

Maura looked around Dan Ystebo's JPL cubicle with distaste, at the old coffee cups and fast-food wrappers amid the technical manuals and rolled-up softscreens. Dan seemed vaguely embarrassed, self-conscious; he folded his arms over his chest.

One softscreen, draped across a partition, showed a blue-green, rippling spacecraft approaching an asteroid. The asteroid was misshapen and almost black, the craters and cracks of its dusty surface picked out by unvarying sunlight.

'Tell me what I'm getting for my money here, Dan.'

He waved his plump hand. 'Near-Earth asteroid 2018JW, called Reinmuth. A ball of rock and ice half a mile across. It's a C-type.' Dan was excited, his voice clipped and wavering, a thin sweat on his brow as he tried to express himself. 'Maura, it's just as we hoped. A billion tons of water, silicates, metals and complex organics - aminos, nitrogen bases. Even Mars isn't as rich as this, pound for pound…'

Dan Ystebo was out of his time, Maura thought. He would surely have preferred to work here in the 1960s and '70s, when science was king, and the great probes were being planned, at outrageous expense: Viking, Voyager, Galileo. But that wasn't possible now.

JPL, initiated as a military research lab, had been taken back by the Army in 2016.

It hadn't been possible to kill off JPL's NASA heritage immediately, not while the old Voyagers still bleeped away forlornly on the rim of the solar system, sending back data about the sun's heliopause and other such useless mysteries.

And Dan Ystebo was making the best of it, in this military installation, with his Nazi-doctored Space Squid. He would probably, Maura realized, have gen-enged her and stuck her in a box if it got him a mission to run.

She said, 'Before somebody asks me, tell me again why we have to bring this thing to Earth orbit.'

'Reinmuth's orbit is close to Earth's. But that means it doesn't line up for low-energy missions very often; the orbits are like two clocks running slightly adrift of each other. The NEOs were never as easy to reach as the space-junkie types like to believe. We'd

have to wait all of forty years before we could repeat Sheena's trajectory.'

'Or bring Sheena home.'

'… Yes. But that's irrelevant anyhow.'

Irrelevant. He doesn't understand, she thought. This had been the hardest point of the whole damn mission to sell, to the House and the public. If we are seen to have killed her for no purpose, we're all finished.

… And now the moment of rendezvous was here.

The firefly spark tracked across the blackened surface. The gentle impact came unspectacularly, with a silent turning of digits from negative to positive.

There was a small splash of grey dust.

And then she could see it, a green fragment of Earth embedded in the hide of the asteroid.

Beneath the translucent floor Sheena could see a grainy, grey-black ground. Dan told her it was a substance older than the oceans of Earth. And, through the curving walls of the ship, she was able to see this world's jagged horizon, barely tens of yards away.

Her world. She pulsed with pride, her chromatophores prickling.

And she knew, at last, she was ready. Sheena laid her eggs.

They were cased in jelly sacs, hundreds of them in each tube. There was no spawning ground here, of course. So she draped the egg sacs over the knot of machinery at the heart of her miniature ocean, which had now anchored itself to the surface of Reinmuth.

Fish came to nose at the eggs. She watched until she was sure that the fish were repelled by the jelly that coated the eggs, which was its purpose.

All this was out of sight of Dan's cameras. She did not tell him what she had done. She could not leave her water habitat; yet she was able to explore.

Small firefly robots set off from the habitat, picking their way carefully over the surface of the asteroid. Each robot was laden with miniature instruments, as exquisite as coral, all beyond her understanding.

But the fireflies were under her control. She used the waldo, the glove-like device into which she could slip her long arms and so control the delicate motions of each firefly.

… Soon the babies were being hatched: popping out of their dissolving eggs one by one, wriggling away, alert, active, questioning. With gentle jets of water, she coaxed them towards sea grass.

Meanwhile, she had work to do.

Sheena sent the fireflies to converge at one pole of Reinmuth. There, patiently, piece by piece, she had them assemble a small chemical factory, pipes and tanks and pumps, and a single flaring nozzle which pointed to the sky. Precious solar panels, spread over the dusty ground, provided power.

The factory began its work. Borers drew up surface regolith and the rock and ice which lay deeper within. Chemical separation processes filtered out methane ice and stored it, while other processes took water ice, melted it and passed it through electrical cells to separate it into its components, oxygen and hydrogen.

This whole process seemed remarkable to Sheena. To take rock and ice, and to transform it into other substances! But Dan told her that this was old, robust technology, practised by NASA and other humans for many times even his long lifetime.

Mining asteroids was easy. You just had to get there and do it.

Meanwhile the young were growing explosively quickly, converting half of all the food they ate to body mass. She watched the males fighting: I am large and fierce. Look at my weapons. Look at me!

Most of the young were dumb. Four were smart.

She was growing old now, and tired easily. Nevertheless she taught the smart ones how to hunt. She taught them about the reef, the many creatures that lived and died there. And she taught them language, the abstract signs Dan had given her. Soon their mantles rippled with questions. Who? Why? Where? What? How?

She did not always have answers. But she showed them the machinery that kept them alive, and taught them about the stars and sun, and the nature of the world and universe, and about humans.

At last the structure at the pole was ready for its test.

Under Sheena's control, simple valves clicked open. Gaseous methane and oxygen rushed together and burned in a stout chamber. Through robot eyes Sheena could see combustion products emerge, ice crystals that caught the sunlight, receding in perfectly straight lines. It was a fire fountain, quite beautiful.

And Sheena could feel the soft thrust of the rocket, the huge waves that pulsed slowly through the hab's water.

The methane rocket, fixed at the axis of the asteroid's spin, would push Reinmuth gradually out of its orbit and send it to intercept Earth.

Dan told her there was much celebration, within NASA. He did not say so, but Sheena understood that this was mainly because she had finished her task, before dying.

Now, she was no longer needed. Not by the humans, anyway.

The young ones seemed to understand, very quickly, that Sheena and all her young would soon exhaust the resources of this one habitat. Already there had been a number of problems with the tightly closed environment loops: unpredictable crashes and blooms in the phytoplankton population.

The young were very smart. Soon they were able to think in ways that were beyond Sheena herself.

For instance, they said, perhaps they should not simply repair this fabric shell, but extend it. Perhaps, said the young, they should even make new domes and fill them with water.

Sheena, trained only to complete her primary mission, found this a very strange thought.

But there weren't enough fish, never enough krill. The waters were stale and crowded.

This was clearly unacceptable.

So the smart young hunted down their dumb siblings, one by one, and consumed their passive bodies, until only these four, and Sheena, were left.

When the storm broke, Dan Ystebo was in his cubicle in the science rooms at JPL, in the middle of an online conference on results from Reinmuth.

Maura Delia stood over him, glaring.

He touched the softscreen to close down the link. 'Senator -'

'You asshole, Ystebo. How long have you known?'

He sighed. 'Not long. A couple of weeks.'

'Did you know she was pregnant before the launch?'

'No. I swear it. If I'd known I'd have scrubbed the mission.'

'Don't you get it, Ystebo? We'd got to the point where the bleeding-heart public would have accepted Sheena's death. But this has changed everything…'

It's over, he thought, listening to her anger and frustration.

She visibly tried to calm down. 'The thing is, Dan, we can't have that asteroid showing up in orbit with a cargo of sentient squid corpses. People would think it was monstrous.' She blinked. 'In fact, so would I.'

He closed his eyes. 'I don't suppose it's any use pointing out how stupid it is to stop now. We spent the money already. We have the installation on Reinmuth. It's working; all we have to do is wait for rendezvous. We achieved the goal, the bootstrap.'

'It doesn't matter,' she said gently, regretfully. 'People are - not rational, Dan.'

'And the future, the greater goal -'

'We're still engaged in a race between opportunity and catastrophe. We have to start again. Find some other way.'

'This was the only chance. We just lost the race.'

'I pray not,' she said heavily. 'Look - do it with decency. Let Sheena die in comfort. Then turn off the rockets.'

'And the babies?'

'We can't save those either way, can we?' she said coolly. 'I just hope they forgive us.' 'I doubt that,' Dan said.

The water which trickled through her mantle was cloudy and stank of decay. She drifted, aching arms limp, dreaming of a male with bright, mindless eyes.

But the young wouldn't let her alone.

Danger near. You die we die. They were flashing the fast, subtle signals employed by a shoal sentinel, warning of the approach of a predator.

There was no predator here, of course, save death itself.

She tried to explain it to them. Yes, they would all die - but in a great cause, so that Earth, NASA, the ocean, could live. It was a magnificent vision, worthy of the sacrifice of their lives.

Wasn't it?

But they knew nothing of Dan, of NASA, of Earth. No. You die we die.

They were like her. But in some ways they were more like their father. Bright. Primal.

Dan Ystebo cleared his desk, ready to go work for a gen-eng biorecovery company in equatorial Africa. All he was hanging around JPL for was to watch Sheena die, and the bio-signs in

the telemetry indicated that wouldn't be so long now.

Then the Deep Space Network radio telescopes would be turned away from the asteroid for the last time, and whatever followed would unfold in the dark and cold, unheard, and to hell with it.

… Here was a new image in his softscreen. A squid, flashing signs at him: Look at me. Dan. Look at me. Dan. Dan. Dan.

He couldn't believe it. 'Sheena?'

He had to wait the long seconds while his single word, translated to flashing signs, was transmitted across space. Sheena 6.

'… Oh.' One of the young.

Dying.Water. Water dying. Fish. Squid. Danger near. Why.

She's talking about the habitat biosphere, he realized. She wants me to tell her how to repair the biosphere. 'That's not possible.'

Not. Those immense black eyes. Not. Not. Not. The squid flashed through a blizzard of body patterns, bars and stripes pulsing over her hide, her head dipping, her arms raised. I am large and fierce. I am parrotfish, seagrass, rock, coral, sand. I am no squid, no squid, no squid.

He had given Sheena 5 no sign for 'liar', but this squid, across millions of miles, bombarding him with lies, was doing its best.

But he was telling the truth.

Wasn't he? How the hell could you extend the fixed-duration closed-loop life-support system in that ball of water to support more squid, to last much longer, even indefinitely?

… But it needn't stay closed-loop, he realized. The Bootstrap hab was sitting on an asteroid full of raw materials. That had been the point of the mission in the first place.

His brain started to tick at the challenge.

It would be a hell of an effort, though. And for what? His NASA pay was going to run out any day, and the soldier boys who had taken back JPL, and wanted to run nothing out of here but low-Earth-orbit milsat missions, would kick his sorry ass out of here sooner than that.

To tell the truth he was looking forward to moving to Africa. He'd live in comfort, in the Brazzaville dome, far from the arenas of the global conflict likely to come; and the work there would be all for the good, as far as he was concerned. None of the ethical ambiguities of Bootstrap.

So why are you hesitating, Ystebo? Are you growing a conscience, at last?

'I'll help you,' he said. 'What can they do, fire me?'

That wasn't translated.

The squid turned away from the camera.

Dan started to place calls.

Sheena 6 was the smartest of the young.

It was no privilege. There was much work.

She learned to use the glove-like systems that made the firefly robots clamber over the asteroid ground. The mining equipment was adapted to seek out essentials for the phytoplankton, nitrates and phosphates.

Even in the hab itself there was much to do. Dan showed her how to keep the water pure, by pumping it through charcoal filters. But the charcoal had to be replaced by asteroid material, burned in sun fire. And so on.

With time, the hab was stabilized. As long as the machines survived, so would the hab's cargo of life.

But it was too small. It had been built to sustain one squid.

So the firefly robots took apart the rocket plant at the pole and began to assemble new engines, new flows of material, sheets of asteroid-material plastic.

Soon there were four habs, linked by tunnels, one for each of Sheena's young, the smart survivors. The krill and diatoms bred happily. The greater volume required more power, so Sheena extended the sprawling solar-cell arrays.

The new habs looked like living things themselves, spawning and breeding.

But already another cephalopod generation was coming: sacs of eggs clung to asteroid rock, in all the habs.

It wouldn't stop, Sheena 6 saw, more generations of young and more habs, until the asteroid was full, used up. What then? Would they turn on each other at last?

But Sheena 6 was already ageing. Such questions could wait for another generation.

In the midst of this activity, Sheena 5 grew weaker. Her young gathered around her.

Look at me, she said. Court me. Love me.

Last confused words, picked out in blurred signs on a mottled carapace, stiff attempts at posture by muscles leached of strength.

Sheena 6 hovered close to her mother. What had those dark-

ening eyes seen? Was it really true that Sheena 5 had been hatched in an ocean without limits, an ocean where hundreds - thousands, millions - of squid hunted and fought, bred and died?

Sheena 5 drifted, purposeless, and the soft gravity of Reinmuth started to drag her down for the last time.

Sheena's young fell on her, their beaks tearing into her cooling, sour flesh.

Dan Ystebo met Maura Delia once more, five years later.

He met her at the entrance to the Houston ecodome, on a sweltering August day. Dan's project in Africa had collapsed when ecoterrorists bombed the Brazzaville dome - two Americans were killed - and he'd come back to Houston, his birthplace.

He took her to his home, on the south side of downtown. It was a modern house, an armoured box with fully-equipped closed life support.

He gave her a beer.

When she took off her resp mask he was shocked; she was wasted, and her face was pitted like the surface of the Moon.

He said, 'An eco-weapon? Another WASP plague from the Chinese -'

'No.' She forced a hideous smile. 'Not the war, as it happens. Just a closed-ecology crash, a prion plague.' She drank her beer, and produced some hardcopy photographs. 'Have you seen this?'

He squinted. A blurred green sphere. A NASA reference on the back showed these were Hubble II images. ‘I didn't know Hubble II was still operating.'

'It doesn't do science. We use it to watch the Chinese Moon base. But some smart guy in the State Department thought we should keep an eye on - that.'

She passed him a pack of printouts. These proved to be results from spectography and other remote sensors. If he was to believe what he saw, he was looking at a ball of water, floating in space, within which chlorophyll reactions were proceeding.

'My God,' he said. 'They survived. How the hell?'

'You showed them,' she said heavily.

'But I didn't expect this. It looks as if they transformed the whole damn asteroid.'

'That's not all. We have evidence they've travelled to some of the other rocks out there. Methane rockets, maybe.'

T guess they forgot about us.'

T doubt it. Look at this.'

It was a Doppler analysis of Reinmuth, the primary asteroid. It was moving. Fuzzily, he tried to interpret the numbers. ‘I can't do orbital mechanics in my head. Where is this thing headed?'

'Take a guess.'

There was a silence.

He said, 'Why are you here?'

'We're going to send them a message. We'll use English, Chinese and the sign system you devised with Sheena. We want your permission to put your name on it.'

'Do I get to approve the contents?'

'No.'

'What will you say?'

'We'll be asking for forgiveness. For the way we treated Sheena.' 'Do you think that will work?'

'No,' she said. 'They're predators, like us. Only smarter. What would we do in their position?' 'But we have to try.'

She began to collect up her material. 'Yes,' she said. 'We have to try.'

As the water world approached, swimming out of the dark, Sheena 46 prowled through the heart of transformed Reinmuth.

On every hierarchical level mind-shoals formed, merged, fragmented, combining restlessly, shimmers of group consciousness that pulsed through the million-strong cephalopod community, as sunlight glimmers on water. But the great shoals had abandoned their song-dreams of Earth, of the deep past, and sang instead of the huge deep future which lay ahead.

Sheena 46 was practical.

There was much to do, the demands of expansion endless: more colony packets to send to the ice balls around the outer planets, for instance, more studies of the greater ice worlds that seemed to orbit far from the central heat.

Nevertheless, she was intrigued. Was it possible this was Earth, of legend? The home of Dan, of NASA?

If it were so, it seemed to Sheena that it must be terribly confining to be a human, to be trapped in the skinny layer of air that clung to the Earth.

But where the squid came from scarcely mattered. Where they were going was the thing.

Reinmuth entered orbit around the water world.

The great hierarchies of mind collapsed as the cephalopods gave themselves over to a joyous riot of celebration, of talk and love and war and hunting: Court me. Court me. See my weapons! I am strong and fierce. Stay away! Stay away! She is mine!…

Things had gone to hell with startling, dismaying speed. People died, all over the planet, in conflicts and resource crashes nobody even kept track of any more - even before the first major nuclear exchanges.

But at least Dan got to see near-Earth object Reinmuth enter Earth orbit.

It was as if his old Project Bootstrap goals had at last been fulfilled. But he knew that the great artefact up there, like a shimmering green, translucent Moon, had nothing to do with him.

At first it was a peaceful presence, up there in the orange, smoggy sky. Even beautiful. Its hide flickered with squid signs, visible from the ground, some of which Dan even recognized, dimly.

He knew what they were doing. They were calling to their cousins who might still inhabit the oceans below.

Dan knew they would fail. There were almost certainly no squid left in Earth's oceans: they had been wiped out for food, or starved or poisoned by the various plankton crashes, the red tides.

The old nations that had made up the USA briefly put aside their economic and ethnic and religious and nationalistic squabbles, and tried to respond to this threat from space. They tried to talk to it again. And then they opened one of the old silos and shot a nuclear-tipped missile at it.

But the nuke passed straight through the watery sphere, without leaving a scratch.

It scarcely mattered anyway. He had sources which told him the signature of the squid had been seen throughout the asteroid belt, and on the ice moons, Europa and Ganymede and Triton, and even in the Oort Cloud, the comets at the rim of the system.

Their spread was exponential, explosive.

It was ironic, he thought. We sent the squid out there to bootstrap us into an expansion into space. Now it looks as if they're doing it for themselves.

But they always were better adapted for space than we were. As if they had evolved that way. As if they were waiting for us to come along, to lift them off the planet, to give them their break.

As if that was our only purpose. Dan wondered if they remembered his name. The first translucent ships began to descend, returning to Earth's empty oceans.

The Fubar Suit

I know I'm still lying here in the regolith, on this dumb little misshapen asteroid, inside my fubar suit. I know nobody's come to save me. Because I'm still here, right? But I can't see, hear, feel a damn thing.

Although I sometimes think I can.

I'm going stir-crazy, inside my own head.

I know they're coming to kill me, though. The little guys. The nems told me that much.

So I have a decision to make.

Them or me.

She drifted in blue warmth, her thoughts dissolving.

… Consciousness burst in on her, dark and dry, dispelling the fug of her prenatal dream. She gasped and coughed, expelling fluid from her lungs.

She was turned around, by huge, confident hands. She was held before a looming face, smiling, wet. Her mother.

There were people all around, naked, thin, anxious. Even so, they smiled at this new birth.

Her eyes were clearing quickly. She - they - were in some kind of huge hall, a vast cylindrical space. The roof, far above, was clear, and some kind of light moved beyond it. There was water in the base of the hall, a great trapped river of it, dense with green. The people were clustered at the edge of the water, on a smooth, sloping beach. Children were playing in the water, which lapped gently against the walls.

Adults clustered around, plucking at her fingers and toes, which grew with a creaking of soft, stretching skin. The growth hurt,

and she cried. She squirmed against her mother, seeking an escape from this dismal cold.

Her mother put her down, on the sloping wall.

Still moist from birth, she crawled away, towards the water.

One of the children came stalking out of the murky water on skinny legs. It was a boy. He spoke to her, pointing and smiling. At first the words made no sense, but they soon seemed to catch. Brother. Sister. Mother. River.

She tried to speak back, but her mouth was soft and sticky.

The boy - her brother - ran back to the water. She followed, crawling, already impatient, already trying to stand upright.

The water was warm and welcoming, and full of sticky green stuff. She splashed out until her head was covered.

Swimming was easier than crawling, or walking.

Her brother showed her how to use her fingers to filter out the green stuff. Algae, he said. She could see little knots and spirals in the green mats.

She crammed the green stuff into her mouth, gnawing at it with her gums, with her growing buds of teeth, sucking it into her stomach. She was very, very hungry.

Her name, they said, was Green Wave.

I was born at the wrong time, in the wrong place.

In the year 2050, when I was eighteen years old, no American was flying into space. We'd ceded the high frontier: the Moon to the Japanese, Mars to the Russians, the asteroid belt to the Chinese. America, without space resources, got steadily poorer, not to mention more decadent. A hell of a time to grow up.

I come from enterprising stock. One of my ancestors made a fortune hauling bauxite on twenty-mule trains out of Death Valley. He also got himself killed, however. Another ancestor was one of the first in the Texas oil fields. And so on.

We lost all the money, of course, long before I was born. But we're a family with one hell of a tradition.

But when I grew up we were rattling around in a box, with no place to go.

I served in the Army. I studied astronomy. I tried to figure an angle: some place out there the Russians and Chinese hadn't got locked up yet.

Finally I settled on the Trojans: little bunches of asteroids outside the main belt, sixty- degrees ahead of and behind Jupiter, shep-

herded by gravity effects. The density of the rocks there is actually greater than in the main belt.

Not only that, the asteroids out there are different from the ones in the belt, which are lumps of basalt and metal. The Trojans are carbonaceous: that is, coated in carbon compounds. And they have water.

And nobody had been out there, ever.

I started to raise money.

My ship, when assembled, was a stack of boxes fifty metres long. At its base was a big pusher plate, mounted on shock absorbers. Around that there were fuel magazines and superconducting hoops. There were big solar-cell wings stuck on the sides.

The drive was a fusion-pulse pusher. It worked by shooting pellets of helium-3 and deuterium out back of the craft, behind the pusher plate, and firing carbon dioxide lasers at them. Each fusion pulse lasts two hundred and fifty nanoseconds. And then another, and another: three hundred microexplosions each second. My acceleration was three per cent of G.

My hab module was just a box, with a reconditioned Russian-design closed-loop life support, and an exercise bicycle.

It was a leaky piece of shit. For instance I watched the engineers fix up a ding in a reaction-control thruster fuel line with Kevlar and epoxy, the way you'd repair your refrigerator. I spent as little as I could on my ship, and a lot on my suit, which is a Japanese design. I called it my fubar suit, my safety option of last resort.

In the event, I was glad to have it.

I was looking at an eighteen-day trip to the Trojans.

I said goodbye to the investors, all of whom had bought a piece of my ass at no risk to themselves. I said goodbye to my daughter. That was hard. I'd said goodbye to her father long before.

I called my ship the Malenfant, after that great explorer. I wasn't exploring, of course, but I always had a little romance in my soul, I think.

When I left Earth orbit, the glow of my drive turned Pacific night into day.

On her second day, she woke up a spindly-legged girl almost as tall, already, as her mother. She spent as long as she could in the water, dragging at the algae. They all did, most of the time.

There was never enough to eat. Sometimes the algae was so thin she could barely taste it sticking to her fingers. She was hungry, the whole time, and she kept on growing.

Her brother touched her shoulder. 'Get out,' he said. His name was Sun Eyes.

'What?'

He took her hand and pulled her from the river. Everybody else was clambering up the curving bank too.

Something was approaching, under the surface of the water, from the darkness at the end of the hall. Something big and sleek and powerful, that churned the water.

Green Wave was one of a row of skinny naked people, waiting by the edge of the water. 'What is it?'

Sun Eyes shrugged. 'It's a Worker.'

'What's a Worker?'

'One of those.'

A lot of her questions were answered like that.

The river wasn't really a river, more a long, stagnant pond. The Workers, coming by once or twice a day, stirred up the liquid. Maybe it was good for the algae, Green Wave speculated.

Anyhow, when a Worker came along, the people had to get out of the way.

As soon as it had gone, she joined the rush to splash back into the water. But the algae was thinner than before. 'The Workers take away the algae,' said Sun Eyes. 'Why? Can't they see we're hungry?' Sun Eyes shrugged.

'I don't like the Workers,' said Green Wave.

Sun Eyes laughed at her.

The facts of her life were these:

This place was called Finger Hall. It was a cylinder, roofed over by some material that allowed in a dim, murky light during the short day. The river ran down its length. The Hall was maybe ten times as tall as an adult human.

The Hall, it was said, was one of five - five Fingers, in fact, lying parallel. The Halls were joined at one end by a big cavern, as her own fingers were joined at her hand. Her mother said she saw this Palm Cavern once, early in her life, three or four days ago. Her brother had never left Finger Hall.

The only drink was river water. The only food was river algae.

That day, her brother spent a lot of time with a girl. And there

was a boy, Churning Wake, who started paying attention to Green Wave. He even brought her handfuls of algae, the only gift he had.

This was her second day. On the third, she came to understand, she would be expected to pair with somebody. Maybe this kid Churning Wake. She would have a baby of her own on the third or fourth day, maybe another.

And on the fifth day -

Her mother was five days old. She was thin, bent, her breasts empty sacks of flesh. Green Wave brought her algae handfuls.

An old man died. His children grieved, then carried his body to the edge of the water. He had been seven days old.

Soon a Worker clambered out of the water. It was a wide, fat disc, half the height of an adult, and its rim was studded with jointed limbs.

The Worker cut up the body of the old man, snip snip, into bloodless pieces. It loaded the chunks of corpse into a hatch on its back, and then closed itself up and slid smoothly back into the water.

'Why did it do that?' Green Wave asked.

'I don't know,' her mother said. She was wheezing. 'You have a lot of questions, Green Wave. His name was Purple Glow, because on the day he was born -'

'Is that it? We're born, we eat algae, we die? In seven days} Is that all there is?'

'We care for each other. We tell the children stories.'

'I don't like it here.'

Her mother laughed, weakly. 'Where else is there?'

I spent the first week throwing up, and drinking banana-flavoured rehydration fluids.

The sun turned to a shrunken yellow disc, casting long shadows. Even Jupiter was just a point of light, about as remote from me as from Earth.

There wasn't a human being within millions of miles. A hell of a feeling.

I found it hard to sleep, listening to the rattles and bangs of my Russian life support. I wore my fubar suit the whole time.

I'd aimed for the largest Trojan, called 624 Hektor. At first it was just a starlike point, but it pulsed in brightness as I watched it. When I got a little closer, I could make out its shape.

624 Hektor: take two big handfuls of Moon, complete with craters and dusty maria. Mould them into egg-shapes, each a hundred miles long. Now touch them together, sharp end to sharp end, and let them rotate, like one almighty peanut.

That's 624 Hektor.

Nobody knows for sure how it got that way. Maybe there was a collision between two normal asteroids which produced a loosely consolidated, fragmented cloud of rubble, which then deformed into this weird compound configuration: two little worlds, made egg-shaped by their mutual attraction, joined in a soft collision.

It was exhilarating to see something no human had witnessed before. For a while, it was as if I really was Reid Malenfant. I sent a long radio letter to my kid, telling her what I could see.

Maybe that will be the last she'll hear of my voice. Because I was still sightseeing when everything fell apart.

I don't know what went wrong. It happened too fast. My best guess is my reaction-control system, little peroxide thrusters, was misaligned. I remembered that ding in the fuel line -

I came in too fast. I tried to turn. I even restarted the fusion pulse drive, but it wasn't enough.

One of the spinning mountains came sweeping up, inexorable, to swat the Malenfant like a fly.

Before the impact, I closed up my fubar suit and bailed out.

The solar panels crumpled, and I saw cells tumble away, little black discs the size of my palm. When my hab module hit it cracked open right down a leaky Russian weld. The drive unit kept working, for a while; it lurched away from the surface, spinning crazily. Other fragments were bounced off the surface, the gravity too low to make them stick: pieces of my ship, scattering into trans-Jovian space.

It took a long time for 624 Hektor to reel me in.

I landed like a dust mote. My boots crunched on lightly-compacted regolith. It felt like loose snow.

I walked towards the wreck. The gravity was so low I kept tumbling away from the ground, as if I was suspended on some huge bungee cord.

Malenfant was fubar, as we used to say in the Army: fucked up beyond all recognition. Just as well I had my fubar suit, I thought.

The stars wheeled around me.

The next day it was her mother's turn.

Green Wave, three days old, was an adult herself now, and her growing pains had diminished. Not her hunger, though. And not her anger.

She stood with Churning Wake at the edge of the water, over her mother's body. 'Why does it have to be like this?' 'It just is,' said Churning Wake.

'But she lived only a few days. In two, three, four days, it will be your turn, Churning Wake. And mine. It isn't right. It isn't enough.'

'But it's all we have. It's all there's ever been.' He took her hand. 'Accept it. Be calm.' 'Like hell.'

After a time, he let her hand go.

A Worker slid through the water, its wake oily. It clattered up the curving shoreline of Finger Hall, and loomed over her mother's corpse. It trailed a fine net which was crammed with algae. It raised up a glinting limb, which started to descend towards her mother's body.

Green Wave lunged forward and grabbed the limb. It was cold and hard, its edges sharp. She twisted. There was a crunching noise, and the limb came away from its socket. Green Wave staggered back, breathing hard. There was a steady ticking from somewhere inside the Worker's algae-crusted case.

Sun Eyes grabbed her shoulders. A day older, her brother already looked closer to death than life, she thought.

'What are you doing?'

'Why do they take away the dead?' she snapped. 'Why do they take away our food? We don't have enough to eat. If we had more to eat, maybe we'd live longer.'

He looked doubtful. 'How long?'

'I don't know' She struggled with the concept. 'Ten days. Maybe twenty.'

'Twenty days? That's ridiculous.'

The Worker had come forward again, and was sawing industriously at her mother's cadaver. It didn't seem impeded by the loss of its limb.

'You have to let her go,' said Sun Eyes.

Green Wave looked at him bleakly.

When the beach was clean of traces of her mother the Worker slid back towards the water. The stump, where she had torn

away the limb, trailed cables. The Worker sank beneath the water and began to surge towards the darkness at the end of Finger Hall.

The people clattered back into the water, to resume their endless feeding.

Green Wave, carrying her Worker limb, started to wade along the river.

Churning Wake stood on the bank, watching her. 'Where are you going?'

'I want to see where it's taking all our food.'

'What about us?"

She laughed. 'Come with me.'

'No,' he said. 'This is my place. We only have a few days. It's up to us not to waste it.'

That made Green Wave hesitate.

What if he was right? Wasn't she gambling away what little was left of her life? Did she really want to risk it all, chasing the unknown?

Maybe she should take time to think this out.

She looked back at Churning Wake, the ribs poking out of his skinny frame. A new infant came crawling past his bony legs, struggling to stand. It was Sun Eyes' son, her nephew, a grandchild her mother had never seen. His wife was already dead.

There had to be, she thought, more than this.

'Come with me,' she said again.

Churning Wake ignored her. He strode into the water and started to feed, with steady determination. Her brother stood hesitating. 'Sun Eyes? Please?'

'You've been trouble since you were born.' 'I'm sorry.'

He walked into the water.

Side by side, they waded through the shallow water, feeding on filtered handfuls of algae paste. Before long, the little community was just a knot of motion in the dim light of the distance. Nobody called them back. They walked on into the cold and dark.

The fubar suit is a smart design. I read the Owner's Manual, which scrolled across the inside of my faceplate.

A fubar suit is a miniature life-support system in itself. It has a small plutonium-based power supply, heavily shielded. It is full

of nanotechnology. It could recycle my wastes, filter my water, break down the solid residue, even feed me on the blue-green algae which would grow in the transparent, water-filled outer layers of the suit.

When I walked across the surface of 624 Hektor, I sloshed and sparkled green. Neil Armstrong would have hated it.

The suit could keep me alive - oh, for two or three weeks. It's a hell of a technical achievement.

Beyond that timescale, it just isn't practical to preserve a full-scale human being in a closed skin-tight container.

Even so, the fubar suit had fallbacks. More drastic options. Mostly untested; the Owner's Manual said I would be voiding manufacturers' guarantees if I exercised them.

I put it off.

I toured 624 Hektor.

With the low gravity it is easy to bound around the equator of either of the little peanut twins. The curvature is tight; I could see I was on a compact ball of rock, curved over on itself, suspended in space. There are craters, some a couple of kilometres across, as if this was a scale model of Luna. Everywhere I found black, sooty carbon compounds, like a dark snow over the regolith.

I hiked around to the contact region.

624 Hektor is a toy world, but even so it is big. I was clambering over a sloping landscape, approaching a hundred-mile mountain that was suspended impossibly over my head, grounded in a broad region of mushed-up regolith and shattered rock.

I lost my sense of the vertical. I actually threw up a couple of times - me, the great astronaut - but some kind of biochemical process inside my helmet cleaned me out.

I could leap from one worldlet to the other.

My perspective shifted. Suspended halfway between the two halves of the peanut, I got a brief sense that these were, indeed, two miniature planets, joined at the hip. But then the other half of the pair started to open out, into a dusty, broken lunar landscape. Real Peter Pan stuff.

I wished I could show it to my kid.

The Worker surged steadily along the length of Finger Hall.

Gradually the walls opened out around them, smooth and high, receding into the distance. At last they reached a new chamber,

much wider and higher than Finger Hall. It was roughly circular, and its roof let in the sunlight. A compact lake lapped at its floor, thick with algae.

There were no people here, but more corridors led off from the rim: five narrow tubes like Finger Hall, and one much broader and darker.

'It's just as they said,' Sun Eyes said. 'This is the Palm Cavern: the Hand from which five Fingers sprout.' He held up his own hand. 'Just like a human hand. And look - that larger tunnel is like a Wrist, leading to an Arm -'

'Maybe.'

The Worker was heading out of the lake, in a new direction. Towards the Wrist.

'We have to go on,' Green Wave said.

'I'm too old for this, Green Wave. Maybe we should go back. Anyhow, nobody's ever been up there before.' 'Then we'll be the first.'

She took his hand and all but dragged him into the water.

The Worker surged silently along the broader corridor that was the Arm, its roof so far above them - seventy, eighty times their height - it was all but impossible to see. There were more Workers here, swimming precisely back and forth along the Arm.

Green Wave and Sun Eyes tired quickly. They were spending so much time just moving, they weren't feeding enough.

The Worker stopped. It was completing small, tight circles in the water, scooping up algae with its trailing nets.

Bringing Sun Eyes, Green Wave moved steadily closer, until the Worker came within an arm's length.

Green Wave grabbed onto the net it trailed. She lodged the detached Worker limb in strands of the net. She helped Sun Eyes get a close grip on the net.

The Worker didn't seem to notice. It wasn't moving so fast; it was easy to hold onto the net, and let the Worker just pull her through the water.

The Worker resumed its steady progress upstream. Some of the net was worn, and she was even able to reach inside and haul out handfuls of algal paste to feed them both.

The walls of the Arm slid steadily past, remote and featureless. On the long beaches there were no signs of people. Maybe, she thought, her own people were alone here, however far this branching series of runnels and gloomy lakes continued.

Sun Eyes slept for a while. His hair, thinning and straggling, drifted into his eyes; Green Wave brushed it back.

The Worker turned a wide corner, and the river opened out. Now they entered a new chamber, containing a broad, glimmering lake, many times wider than the Palm Cavern they'd seen before. The roof here, far above them, was all but transparent, and Green Wave could see the sun's small disc, and many lesser lights. The water was thick with algae; she merely had to dip her hand in to pull out great fistfuls of sticky paste.

'Fingers,' she said.

'What?'

'Fingers. A Hand. An Arm. If that's all true, this must be the Chest. Or the Stomach.'

'You don't know what you're talking about,' Sun Eyes said tiredly.

'If I'm right, that way must be the Head.' 'The Head of what?' 'How should I know?'

In the direction she pointed, there was a broad, dark exit. The Neck? A series of thick pipes snaked out of the lake, and passed into the Neck. There was a system of net hoppers in front of the pipes; the water was greener there, as if richer with algae. Workers clustered around the hoppers, working busily, dumping in algae from their own nets. She pictured some prone giant, sucking nutrient out of this algal hopper in its Stomach.

Sun Eyes clutched at the net. 'We're leaving the shore. I can't feel the floor.'

It was true. The Worker was forging its way across the lapping surface of the lake; they were already a long way from the curving walls, heading for the deeper water under the high arch of the Stomach roof.

And now there was something new. Something deep under the water. It was a light, flickering, bubbling. No: a bank of lights, in neat rows, stretching off all around her.

'What do you think it is?' she whispered.

T don't know. I only ever saw lights in the sky.'

'Maybe it's another sun, under the water. Maybe -'

But now a hatch on top of the Worker's back was opening up. A limb came looping over, and plucked objects out of the hatch. The objects, dried-up and irregular, were the remnants of Green Wave's mother. The Worker dumped them into the water.

They fell quickly, but when they hit the underwater suns there was a ferocious, silent bubbling.

'So that's what happens to dead people,' said Sun Eyes. 'That's what will happen to us.'

The hatch closed, and the Worker swam in lazy, broadening circles.

'I'm tired,' Sun Eyes said.

She fed him more handfuls of algal paste.

I lay on my back, face up to the stars, unsure if I would ever get up again.

I let the nems get to work.

I wish I could say it was painless.

The idea is simple.

The fubar suit has constructed a stable, simplified, long-duration ecosphere inside itself. Most of the volume is just air, but there is a shallow water lake pooling in the suit's back, arms and legs. There is blue-green algae growing in the lake, feeding on sunlight, giving off carbon dioxide - spirulina, according to the Owner's Manual, full of proteins, vitamins and essential amino acids. The other half of the biocycle is a community of little animals, living inside the suit. They are like humans: eating the algae, drinking the water, breathing in oxygen, breathing out carbon dioxide. Their wastes, including their little dead bodies, go to a bank of SCWOs - supercritical water oxidizers - superhot liquid steam which can oxidize organic slurry in seconds. A hell of a gadget. It can even sustain underwater flames; you have to see it to believe it.

Of course you can't close the loops completely. But I was able to plug the suit into the surface of 624 Hektor and supplement the loops with raw materials - carbon compounds, hydrates. It would last a long time.

It's all constructed and maintained by the nems - nano-electro-mechanical systems, tiny crab-like robots with funny little limbs. The suit is full of them. They're even burrowing their way out into the asteroid surface, in search of raw materials.

I read all about the nems in the Owner's Manual. The technology is neat; the nems are run by chips lithographed by high-energy proton beams, and they store data in chains of fluorine and oxygen atoms on the surface of dinky little diamonds -

I always liked Japanese gadgets.

But I should stick to the point.

Little guys. Of course they are like miniature people. What else could they be? They are made out of me.

There's no nice way of putting this. The fubar suit couldn't keep me alive - not as sixty kilograms of eating, breathing, excreting woman anyhow. So the nems took me apart.

The nems used my body water to make the lakes, and my meat - some of it - to make the little guys.

What's left of me is my head. My head is sustained - my brain is kept alive - by nutrients from the little biosphere that takes up the space my body used to occupy. One day, the theory goes, the medics will retrieve me and will reassemble me, in some form, with more nanotech.

It's grotesque. Well, it's not what I wanted. I'm only thirty-eight years old. I have a kid, waiting for me.

I just didn't have any choices left.

The fubar suit was a last resort. It worked, I guess.

I just wish they'd tested it first. Damn those Japanese.

Little humans. They are supposed to look like us, bug-sized or not. They are supposed to be able to move around; the water surfaces in there are doped somehow, so the little guys aren't locked in place by surface tension. They are supposed to breed quickly and eat and breathe and die back, and just play their part in the two-component biosphere, keeping me alive.

What they're not supposed to be is smart. What they're not supposed to do is ask questions.

What a mess.

When she woke, she was so stiff it was all she could do to unhook her claw-like hands from the net. Sun Eyes was still sleeping, shivering gently. His scalp was all but hairless now, his face a mask of wrinkles.

She looked around. The Worker was close to the shore of this great Stomach cavern, but it was working its way back towards the exit from which it had emerged.

Time to get off, she thought.

She shook Sun Eyes. His eyes were crusted with sleep. 'Green Wave? I can't see so well. I'm cold.' 'Come on. I'll get you to the shore.'

She helped him disentangle himself from the netting. His legs unfolded from his chest with painful slowness.

At last they were standing, in water that came to their waists. She slid an arm around him, and they walked to shallower water, scooping up algae. Green Wave still carried her purloined Worker limb.

The Worker, apparently oblivious to the loss of its passengers, surged steadily towards the exit to the Arm. 'It's going back,' Sun Eyes said. 'I know. We have to go on.' 'What for?' 'I'm not sure.' 'Where?'

She pointed. 'That way. The Head.'

They began to work their way around the complex, sculpted shoreline, towards the exit Green Wave had labelled the Neck. They walked in the shallows. They could only manage a slow pace, such was Sun Eyes' condition.

She felt a deep stab of regret. She'd taken Sun Eyes away from where he should be, with his children and grandchildren. And she was old herself now - too old to have a life of her own, too old for children. She wondered what had happened to Churning Wake, if he was surrounded now by splashing children who might have been hers.

They neared the sharp folds in the ground that marked the entrance to the Neck. She could see the big pipes that carried water up from the lake. The pipes were clear, and she could see thick, greenish, rich fluid within. Food, taken away from people who needed it. A diffuse anger gathered.

They walked into the Head.

It was darker here. Most of the light came from the Stomach lake, a greenish glow at the mouth of this broad tunnel.

There was little free water here, little food. But still she urged Sun Eyes on. 'Just a bit more,' she said.

They reached a pit in the ground, twenty or thirty paces across.

She sat Sun Eyes down, propping him up against a wall.

She lay on her stomach. The pit was pitch dark. It was the first time in her life she'd seen a breach in the floor. Her imagination raced.

She reached down into the pit.

At first she could feel nothing but the smooth flooring. But that came to an end quickly, and below it she could feel beneath, to some much rougher, looser material. It felt damp and cold.

There were even algae here, clinging to the walls in clumps.

She could hear Workers doing something, perhaps chewing at the loose rubble down there. Building the pit, onwards and outwards.

She straightened up stiffly. She tried to see deeper into the Head - there were suggestions of vast, sleeping forms there, perhaps an immense face - but there was no light, no free water. She couldn't go any further.

She went back to Sun Eyes. He seemed to be sleeping.

She told him what she'd found.

'Maybe there are worlds beyond this one.' Her imagination faltered. 'If we are crawling through the body of some human form, maybe there is another, still greater form beyond. And perhaps another beyond that - an endless nesting…'

He slumped against her shoulder.

She laid his light, wizened body down against the floor. In the darkness she could feel his ribs, the lumps of his joints. Her anger flared up, like the light of a new sun.

I know I'm still lying here in the regolith, on this dumb little misshapen asteroid, inside my fubar suit. I know nobody's come to save me. Because I'm still here, right? But I can't see, hear, feel a damn thing.

Although I sometimes think I can.

I'm going stir-crazy, inside my own head.

I know they're coming, though. The little guys. The nems told me that much.

They aren't supposed to be smart, damn it!

But the nems will stop them, if I tell them.

So I have a decision to make. I could stop them.

After all, it's them or me.

She got to her feet. She picked up her battered Worker limb, and stumbled out of the Neck, towards the light of the Stomach lake.

She started to batter at the feeder pipes with the Worker limb, her only tool.

The pipes were broad, as thick as her waist, but they punctured easily. Soon she had ripped fist-sized holes in the first pipe, and algae-rich water spilled down over the flooring, and flowed steadily back into the lake. She kept it up until she'd severed the pipe completely.

Then she started on the next pipe.

The Workers didn't react. They just swam around in their complacent circles, piling up the net hopper with algae that wasn't going anywhere any more.

She worked until all the pipes were broken.

She threw away her Worker limb, and lay down where she was, in the slimy, brackish water she'd spilled. She licked at the floor, sucking in a little algal paste, and let herself sleep.

Sometimes I think humans aren't supposed to be out here at all. Look at me, I'm grotesque. These little guys, on the other hand, might be able to survive. Even prosper.

A hell of a shock for those smug Chinese in the asteroid belt, when a swarm of little Americans comes barrelling in from the orbit of Jupiter.

What the hell. It didn't look as if anyone was coming for me anyhow.

Funny thing is, I feel cold. Now, that's not supposed to happen, according to the Owner's Manual.

It was hard to wake up. Her eyes didn't open properly. And when they did, they wouldn't focus.

She lifted up her hand, and held it close so she could see. Her skin was brown and sagging and covered in liver spots.

She got to her feet, and stumbled down the slope.

She stood at the edge of the water, peering at the Workers, until her rheumy, ruined eyes made out one which didn't look quite right. One that was missing a limb.

She struggled through water that seemed thick and resistant, until she had caught hold of the Worker's net, and it was pulling her away from the shore.

With any luck this creature would, unwitting, take her home. She'd be a sack of bones by then, of course, but that didn't matter. The important thing was that someone would see, and maybe connect her with the enriching of the water, and wonder what she'd found.

More would come, next time. Children, too.

They would find that pit, up in the Neck, the way out of the world.

She smiled.

The water was warm around her.

She wondered what had happened to Sun Eyes. Maybe he was somewhere beneath her now, fizzing in the light of those underwater suns.

She closed her eyes. She drifted in blue warmth, her thoughts dissolving.

Grey Earth

She was old now. The cold dug into her joints and her scars, and the leg she had fractured long ago, more than it used to.

She still called herself Mary. But she was one of the last to use the old names. And the people no longer called themselves Hams - for there were no Skinnies here who could call them that, none save Nemoto - and they were no longer called the People of the Grey Earth, for they had come home to the Grey Earth, and had no need to remember it.

There came a day, when they put old Saul in the ground, when Mary found herself the last to remember the old place, the Red Moon where she had been born.

Outside the cave that day there was only darkness, the still darkness of the Long Night, broken by the stars that sprinkled the cloudless black sky. Mary's deep past was a place of dark green warmth. But her future lay in the black cold ground, where so many had gone before her: Ruth, Joshua, Saul, even one of her own children.

But it didn't matter.

All that mattered were her skins, and the warm fug of gossip and talk that filled the cave, and the warm sap that bled from the root of the blood-tree that pierced the cave roof, on its way to seek out the endless warmth that dwelled in the belly of this earth, this Grey Earth.

All that mattered was today. Comparisons with misty other times - with past and future, with a girl who had fought and laughed and loved on a different world, with the bones that would soon rot in the ground - were without meaning.

Nemoto was not so content, of course.

Day succeeds empty day.

At first, on arriving here, I dreamed of physical luxuries: running hot water, clean, well-prepared food, a soft bed. But now it is as if my soul has been eroded down to an irreducible core. To sleep in the open on a bower of leaves no longer troubles me. To have my skin coated in slippery grime is barely noticeable.

But I long for security. And I long for the sight of another human face.

Sometimes I rage inwardly. But I have no one to blame for the fact that I have become lost between worlds, between realities.

And when I become locked inside my own head, when my inner distress becomes too apparent, it disturbs the Hams, as if I am becoming a danger to them.

So I have learned not to look inward.

I watch the Hams as they shamble about their various tasks, their brute bodies wrapped up in tied-on animal skins like Christmas parcels. All I see is their strangeness, fresh every day. They will complete a tool, use it once, drop it, and move on. It is as if every day is the very first day of their lives, as if they wake up to a world created anew.

It is obvious that their minds, housed in those huge skulls, are powerful, but they are not like humans'. But then they are not human. They are Neandertal.

This is their planet. A Neandertal planet.

Still, I try to emulate them. I try to live one day at a time. It is comforting.

My name is Nemoto. If you find this diary, if you understand what I have to say, remember me.

Nemoto was never content. Even in the deepest dark of the Long Night, she would bustle about the cave, arguing with herself, agitated, endlessly making her incomprehensible objects. Or else she would blunder out into the dark, heavily wrapped in furs, perhaps seeking her own peace in the frozen stillness beyond.

Few watched her come and go. To the younger folk, Nemoto had been here all their lives, a constant, unique, somewhat irritating presence.

But Mary remembered the Red Moon, and how its lands had run with Skinnies like Nemoto.

Mary understood. Mary was of the Grey Earth, and she had come home. But Nemoto was of the Red Moon - or perhaps of

another place, a Blue Earth of which she sometimes spoke - and now it was Nemoto who had been stranded far from her home.

And so Mary made space for Nemoto. She would protect Nemoto when the children were too boisterous with her, or when an adult challenged her, or when she fell ill or injured herself. She would even give her meat to eat. But Nemoto's thin, pointed jaw could make no impression on the deep-frozen meat of the winter store, and nor could her shining tools. So Mary would soften the meat for her with her own strong jaws, chewing it as she would to feed a child.

But one day Nemoto spat out her mouthful of meat on the floor of the cave. She raged and shouted in her jabbering Skinny tongue, expressing disgust. She pulled on her furs and gathered her tools, and stamped out of the cave.

Time did not matter during the Long Night, nor during its bright twin, the Long Day. Nemoto was gone, as gone as if she had been put in the ground, and she began to soften in the memory.

But at last Nemoto returned, as if from the dead. She was staggering and laughing, and she carried a bundle under her arms. The children gathered around to see.

It was a bat, still plump with its winter fat, its leathery wings folded over. The bat had tucked itself into a tree hollow to endure the Long Night. But Nemoto had dug it out, and now she put it close to a warm root of the blood-tree to let it thaw. She jabbered about how she would eat well of fresh meat.

The bat revived briefly, flapping its broad wings against the cave floor. But Nemoto briskly slit its throat with a stone knife, and began to butcher it.

Nemoto consumed her bat, giving warm titbits to the children who clustered around to see. She sucked marrow from its thread-thin bones, and gave that to the children as well. But when she offered the children bloated, pink-grey internal organs, mothers pulled the children away.

That was the last time Nemoto was ever healthy.

Mary eats her meat raw, tearing at it with her shovel-shaped teeth and cutting it with a flake knife; every so often she scrapes her teeth with the knife. And as her powerful jaw grinds at the meat, great muscles work in her cheeks.

Mary is short, robust, heavily built. She is barrel-chested, and her arms and massive-boned legs are slightly bowed. Her feet are

broad, her toes fat and bony. Her massive hands, with their long powerful thumbs, are scarred from stone chips. Her skull, under a thatch of dark brown hair, is long and low with a pronounced bulge at the rear. Her face is pulled forward into a great prow fronted by her massive, fleshy nose; her cheeks sweep back as if streamlined, but her jaw, though chinless, is massive and thrust forward. From her lower forehead a great ridge of bone thrusts forward, masking her eyes. There is a pronounced dip above the ridges, before her shallow brow leads back into a tangle of hair.

She is Neandertal. There can be no doubt.

She lives - I live - in a system of caves. There is an overpowering stench of people, of sweat, wood smoke, excrement and burning fur, and a musty, disagreeable odour of people who don't wash.

Every move the Hams make, every act they complete, from cracking open a bone to bouncing a child in the air, is suffused with strength. They suffer a large number of injuries, bone fractures and crushing injuries and gouged and scarred skin. But then their favoured hunting technique is to wrestle their prey to the ground. It is like living with a troupe of rodeo riders.

The Hams barely notice me. They are utterly wrapped up in each other. Some of the children pluck at the remnants of my clothing with their intimidatingly strong fingers. But otherwise the Hams step around me, their eyes sliding away, as if I am a rock embedded in the ground. I sometimes theorize that they are only truly conscious in social interactions; everything else - eating, making tools, even hunting - is done in a rapid blur, as I used to drive a car without thinking. Certainly, to a Neandertal, by far the most fascinating things in the world are other Neandertals.

They are not human. But they care for their children, and for their ill and elderly. However coolly the Hams treat me, they have not expelled me, which is how I survive.

I brought them here, from the Red Moon. This tipped-up Earth is their home. They remembered it during the time of their exile on another world. Remembered it for forty thousand years, an unimaginable time.

I imagined I would be able to get away from here, to home. It did not happen that way.

There was a time of twilights, blue-purple shading to pink. And then, at last, the edge of the sun was visible over the horizon: just

a splinter of it, just for an hour, but it was the first time the sun had shown at all for sixty-eight days.

When the people saw the light they came bursting out of the cave.

They scrambled onto the low bluff over the cave, where the blood-tree stood: leafless and gaunt now, but its blood-red sap coursed with the warmth it had drawn from the Grey Earth's belly, the warmth that had sustained the people through the Long Night. The people danced and capered and threw off their furs. Then they retreated to the warmth of the cave, where there was much chatter, much eating, much joyous sex.

Though it would be some time yet before the frozen lakes and rivers began to thaw, there was already a little meltwater to be had. And the first hibernating animals - birds and a few large rats - were beginning to stir, sluggish and vulnerable to hunting. The people enjoyed the first thin fruits of the new season.

But Nemoto's illness was worse.

She suffered severe bouts of diarrhoea and vomiting. She steadily lost weight, becoming, in the uninterested eyes of the people, even more gaunt than she had seemed before. And her skin grew flaky and sore. The children would watch in horrified fascination as she shucked off her furs and her clothes, and then peeled off bits of her skin, as if she would keep on until nothing was left but a heap of bones.

Mary tried to treat the diarrhoea. She brought water, brine from the ocean diluted by meltwater. But she did not know how to treat the poisoning which was working its way through Nemoto's system.

The key incident in the formation of the Earth was the collision of proto-Earth with a wandering planetesimal larger than Mars. This is known as the Big Whack.

It is hard to envisage such an event. The projectile that ended the Cretaceous era, sending the dinosaurs to extinction, was perhaps six miles across. The primordial impactor was some four thousand miles across. It was a fully formed planet in its own right. And the collision released two hundred million times as much energy as the Cretaceous impact.

The proto-Earth's oceans were boiled away. About half of Earth's crust was demolished by the impact. A tremendous spray of liquid rock was hurled into space. The impactor was stripped

of its own mantle material, and its core sank into the interior of the Earth. Much of the plume fell back to Earth. Whatever was left of the atmosphere was heated to thousands of degrees.

The remnant plume settled into a ring around the Earth, glowing white hot. As it cooled it solidified into a swarm of moonlets. It was like a replay of the formation of the solar system itself. The largest of the moonlets won out. The growing Moon swept up the remnant particles, and under the influence of tidal forces, rapidly receded from Earth.

Earth itself, meanwhile, was afflicted by huge tides, a molten crust and savage rains as the ocean vapour fell back from space. It took millions of years before the rocks had cooled enough for liquid water to gather once more.

Everything was shaped in those moments of impact: Earth's spin, the tilt of the axis that gives us seasons, the planet's internal composition, the Moon's composition and orbit.

But it didn't have to be that way.

Such immense collisions are probably common in the formation of any planetary system. But the impact itself was a random event: chaotic, in that small differences could have produced large, even unpredictable consequences. The impactor might have missed Earth altogether - but that would have left Earth with its original atmosphere, a crushing Venus-like blanket of carbon dioxide. Or the impactor might have hit at a subtly different angle. A single Moon isn't necessarily the most likely outcome; many collision geometries would produce two twin Moons, or three or four, or ring systems like Saturn's. And so on.

Many possibilities. All of which, somewhere in the infinite manifold of universes, must have come to pass.

I know this because I have visited several of those possibilities.

The days lengthened rapidly.

The ice on the lakes and rivers melted, causing splintering crashes all over the landscape, like a long, drawn-out explosion. Soon the lakes were blue, though pale cores of unmelted ice lingered in their cores.

Life swarmed. In this brief temperate interval between deadly cold and unbearable heat, plants and animals alike engaged in a frenzied round of fighting, feeding, breeding, dying.

The people moved rapidly about the landscape. They gathered the fruit and shoots that seemed to burst out of the ground. They

hunted the small animals and birds that emerged from their hibernations to seek mates and nesting places.

And soon a distant thunder sounded across the land: relentless, billowing day and night across the newly green plains, echoing from green-clad mountains. It was the sound of hoofed feet, the first of the migrant herds.

The men and women gathered their weapons, and headed towards the sea.

It turned out to be a herd of giant antelopes. They were slim and streamlined, the muscles of their legs and haunches huge and taut, the bucks sporting huge folded-back antlers. And they ran like the wind. Since most of this tilted world was, at any given moment, freezing or baking through its long seasons, migrant animals were forced to travel across thousands of kilometres, spanning continents in their search for food, water and temperate climes. Speed and endurance were of the essence for survival.

But predators came too, sleek hyenas and cats stalking the vast herds. Though the antelopes were mighty runners - fuelled by high-density fat, able to race for days without a break - there were always outliers who could not keep up: the old, the very young, the injured, mothers gravid with infants. And it was on these weaker individuals that the predators feasted.

Those predators included the people, who inhabited a neck of land between two continents, a funnel down which the migrant herds were forced to swarm.

The antelope herd was huge. But it passed so rapidly that the great river of flesh was gone in a couple of days. And after another day, the predator packs that stalked it had gone too.

The people ate their antelope meat and sucked rich marrow, and gathered their fruit and nuts and shoots, and waited for their next provision to come to them, delivered up by the tides of the world.

But the next group of running animals to come by was small - everyone could sense that - and everybody knew what they were, from their distinctive, high-pitched cries.

Everybody lost interest. Everybody but Nemoto.

The Hams are aware of the coming and going of the herds of migrating herbivores on which they rely for much of their meat, and are even able to predict them by the passage of the seasons. But Hams do not plan. They seem to rely on the benison of the

world to provision them, day to day. It means they sometimes go hungry, but not even that dents their deep, ancient faith in the world's kindness.

I remember a particular hunt. I followed a party of Hams along a trail through the forest.

They stopped by a small tree, thick with hanging fibres, and with dark hollows showing beneath its prop roots. White lichen was plastered over its trunk, and a parasitic plant with narrow, dark-green leaves dangled from a hollow in its trunk. A Ham cut a sapling and pushed it into one deep dark hollow, just above the muddy mush of leaves and detritus at the base of the tree.

A deep growling emerged from beneath the roots of the tree.

Excited, the Hams gathered around the tree and began to haul at it, shaking it back and forth. To my amazement they pulled the tree over by brute force, just ripping the roots out of the ground. Out squirmed a crocodile, a metre long, jaws clamped at the end of the pole. It was dark brown with a red-tinged head, huge eyes, and startlingly white teeth.

It was a forest crocodile. These creatures come out at night. They eat frogs, insects, flightless birds, anything they can find. They have barely changed in two hundred million years.

This world is full of such archaisms and anachronisms - like the Hams themselves. Of course it is. For it is not my world, my Earth. It is not my universe.

The Hams fell on the crocodile in their brutal, uncompromising way. They rolled it onto its back. One woman took a stone hand-axe and sliced off the right front leg, then the left. The animal, still alive, struggled feebly; its screams were low, like snoring. When the woman opened its chest it slumped at last.

I confronted Abel. 'Why didn't you kill it before starting the butchering?'

The big man just looked back at me, apparently bemused.

These are not pet-owners. They aren't even farmers. They are hunter-gatherers. They have no reason to be sentimental about the animals, to care about them. My ancestors were like this once.

Not only that: the Hams do not anthropomorphize. They could not imagine how it would be to suffer like the animal, for it was a crocodile, not a person.

I turned away from the blood, which was spreading over the ground.

Sickly, gaunt, enfeebled, her clothing stained with her own shit and piss, her eyes so weak she had to wear slitted skins over her face, Nemoto seemed enraged by the approach of these new arrivals. She gathered up her tools of stone and metal, and hurried out of the cave towards the migrants.

Mary followed Nemoto, catching her easily.

Soon they saw the Running-folk.

There were many of them, men, women, children. They had broken their lifelong trek at a river bank. They were splashing water into their mouths, and over their faces and necks. The children were paddling in the shallows. They were all naked, all hairless save for thatches on their scalps and in their groins and arm-pits.

They would never have been considered beautiful by a human, for their legs were immensely long and their chests expanded behind huge rib cages, giving them something of the look of storks. But they had the faces of their Homo erectus ancestors, small and low-browed with wide, flat nostrils.

And Nemoto was stalking towards this gathering, waving her arms and brandishing her weapons. 'Get away! Get away from there, you brutes!'

Some of the adults got to their feet, their legs unfolding, birdlike. Mary could hear their growls, though she and Nemoto were still distant.

The first rock - crudely chipped, as if by a child - landed in the dirt at their feet.

Mary grabbed Nemoto's arm. Nemoto struggled and cursed, but Mary held her effortlessly. She dragged Nemoto back out of range of the stones.

The Runners settled again to their bathing and drinking. They stayed where they were for most of that long day, and so did Nemoto, squatting in the dirt with scarcely a motion, staring at the Runners.

Mary stayed with her, growing increasingly hot and thirsty.

At last, as the evening drew in, the Runners got to their feet, one by one, picking up their long hinged legs. And then they began to move off along the river. They became lanky silhouettes against the setting sun, and the river gleamed gold.

Nemoto stalked down towards the river.

Here, just where the Runners had settled, there was a shell of white and black, cracked open. It was the thing Nemoto called a

lander. Once, Nemoto had used it to bring the Hams here, to the Grey Earth, to home. Nemoto clambered inside the shattered hull. After so many cycles of the Grey Earth's ferocious seasons, there was little left of the interior equipment now. Mary saw how birds and wasps and spiders had made their home here, and grass and herbs had colonized the remnants of the softer materials.

Mary thought she understood. Though it had been broken open the moment it had fallen to the ground, Nemoto had done her best to protect and preserve the wreck of the lander. Perhaps she wanted it to take her home.

But the lander remained resolutely smashed and broken, and Nemoto could not even persuade the people to get together to haul it away from the river.

As the light seeped out of the sky, Nemoto, at last, came away from the wreck. Mary took her arm, and shepherded her quickly towards the security of the cave, for the predators hunted at sunset.

It proved to be the last time Nemoto ever left the community.

I do not know how this came to be, this manifold, this cosmic panoply, this proliferation of realities.

There is a theory that our universe grew from a seed, a tiny piece of very high-density material that then inflated into a great volume of spacetime, with planets and stars and galaxies. This was the Big Bang. But perhaps that seed was not unique. Perhaps there is a sea of primordial high-density matter-energy - a sea where temperatures and densities and pressures exceed anything in our universe, where physics operates according to different laws

- and within this sea universes inflate, one after another, like bubbles in foam. These bubble-universes would have no connection with each other. Their inhabitants would see only their own bubble, not the foam itself.

That is my legend. The Hams' legend is that the Old Ones created it all. Who is to say who is right? How could we ever know?

Whatever the origin of the manifold, within it there could be an infinite number of universes. And in an infinite ensemble, everything which is logically possible must - somewhere, somehow -come to pass.

Thus there must be a cluster of bubble-spaces with identical histories up to the moment of Earth's formation, the Big Whack

- and differing after that only in the details of the impact itself,

and their consequences. I imagine the possible universes arrayed around me in phase space. And universes differing only in the details of the Earth-Moon impact must somehow be close to ours in that graph of the possible.

I know this from personal experience.

For me it began when a new Moon appeared in Earth's sky: a fat Moon, a Red Moon, replacing poor dead Luna. I travelled to that Moon on a quixotic jaunt with Reid Malenfant, ostensibly in search of his lost wife, Emma Stoney. There we encountered many hominid forms - some more or less human, some not - all refugees from different reality strands, swept away by that Red Moon, which slides in sideways knight's moves between universes.

Just as Malenfant and 1 were swept away, when my own Earth, Blue Earth, disappeared from the Moon's sky. I knew immediately that I could never go home.

To fulfil a pledge foolishly made to these Hams by Emma Stoney, I agreed to use our small Earth-Moon ferry spacecraft to carry the Hams back to their Grey Earth - when the opportunity presented itself, as our wandering Moon happened that way. Once I was off the Red Moon, with a spacecraft, 1 vaguely imagined that I would be able to go further, to get away from the deadening menticulture that rapidly emerged among the stranded on the Red Moon. But it was not to be; 1 crashed here, and when the Red Moon wandered away from the sky, I was left doubly stranded.

The Red Moon is an agent of human evolution. That is why it wanders. Its interstitial meandering is a mixing device, an artefact of the Old Ones, who may even have manufactured this vast mesh of realities.

So I believe.

But whatever the purpose of that Moon's wandering, it destroyed my own life.

For the Hams, for Julia, the Grey Earth is home. For me, this entire universe is a vast prison.

The air grew hotter yet, approaching its most violent peak of temperature, even though the sun still lingered beneath the horizon for part of its round, even though night still touched the Grey Earth. Soon the fast-growing grasses and herbs were dying back, and the migrant animals and birds had fled, seeking the temperate climes.

The season's last rain fell. Mary closed her eyes and raised her open mouth to the sky, for she knew it would be a long time before she felt rain on her face again.

The ground became a plain of baked and cracked mud.

The people retreated to their cave. Just as its thick rock walls had sheltered them from the most ferocious cold of the winter, so now the walls gave them coolness. And just as the people had drawn warmth from the sap of the blood-tree, pumped up from the ground, now the tree let its sap carry its excess heat down into the ground, and its tangle of roots cooled the cave further.

The people ate the meat they had dried out and stored in the back of their cave, and they drank water from the drying rivers and lakes, and dug up hibernating frogs, fat sacks of water and meat that croaked resentfully as they were briskly killed.

Nemoto could not leave the cave, of course. Long before the heat reached its height, her relentless illness had driven her to her pallet, where she remained, unable to rise, with a strip of skin tied across her eyes. But Mary brought her water and food.

At length there came a day when the sun failed even to brush the horizon at its lowest point. From now on, for sixty-eight days, it would not rise or set, but would make meaningless circles in the sky, circles that would grow smaller and more elevated.

The Long Day had begun.

And still the great blood-tree grew, drinking in the endless light of the sun and the water it found deep beneath the ground, so that sometimes the roots that pierced the cave writhed like snakes.

Here is how, or so I have come to believe, this Red Moon has played a key role in human evolution.

Consider. How do new species arise, of hominids or any organism?

Isolation is the key. If mutations arise in a large and freely mixing population, any new characteristic is diluted and will disappear within a few generations. But when a segment of the population becomes isolated from the rest, dilution through interbreeding is prevented. Thus the isolated group may, quite rapidly, diverge from the base population. And when those barriers to isolation are removed, the new species finds itself in competition with its predecessors. If it is more fit, in some sense, it will survive by out-competing the parent stock. If not, it declines.

When our scientists believed there was only one Earth, they

developed a theory of how the evolution of humanity occurred. The ape-like bipeds called Australopithecines gave rise to tool users, who in turn produced tall erect hairless creatures capable of walking on the open plain, who gave rise to various species of Homo sapiens - the genus that includes myself. It is believed that at some points in history there were many hominid species, all derived from the base Australopithecine stock, extant together on the Earth. But my kind - Homo sapiens sapiens - proved the fittest of them all. By out-competition, the variant species were removed.

Presumably, each speciation episode was instigated by the isolation of a group of the parent stock. We assumed that the key isolating events were caused by climate changes: rising or falling sea levels, the birth or death of forests, the coming and going of glaciation. It was a plausible picture - before we knew of the Red Moon, of the Grey Earth, of other Moons and Earths.

Assume that the base Australopithecine stock evolved on Earth

- my Earth. Imagine that some mechanism scooped up handfuls of undifferentiated Australopithecines and, perhaps some generations later, deposited them on a variety of subtly different Earths.

It is hard to imagine a more complete isolation. And the environments in which they were placed might have had no resemblance to those from which they were taken. In that case our Australopithecines would have had to adapt or die.

And later, samples of those new populations were swept up in their turn, and handed on to other Earths, where they were shaped again. Thus the Hams, with their power and conservatism, have been shaped by the brutal conditions of this Grey Earth.

This is my proposal: that hominid speciation has been driven by the transfer of populations between parallel Earths. It is fantastic, but logical.

If this is true, then everything about us - everything about me

- has been shaped by the meddling of the Old Ones, these engineers of worlds and hominids, for their own unrevealed, unfathomable purpose, just as my own life story - too complicated to set out here - has become a scrawl across multiple realities.

What remains unclear is why the Old Ones, if they exist, should wish to do this. Perhaps their motives were somehow malicious, or somehow benevolent; perhaps they wished to give the potential of humankind its fullest opportunity of expression.

But their motive is scarcely material.

What power for mortals to hold. What arrogance to wield it.

Nemoto said she would not go into the ground until she saw another night. But she grew steadily weaker, until she could not raise her body from its pallet of moss, or clean herself, or even raise her hands to her mouth.

Mary cared for her. She would give Nemoto water in sponges of mashed-up leaf, and when Nemoto fouled herself Mary cleaned her with bits of skin, and she bathed her body's suppurating sores with blood-tree sap.

But Nemoto's skin continued to flake away, as the slow revenge of the bat disturbed from its hibernation took its gruesome course.

There came a day when the sun rolled along the horizon, its light shimmering through the trees which flourished there. Mary knew that soon would come the first night, the first little night, since the spring. So she carried Nemoto to the mouth of the cave - she was light, like a thing of twigs and dried leaves - and propped her up on a bundle of skins, so that her face was bathed in the sunlight.

But Nemoto screwed up her face. ‘I do not like the light,' she said, her voice a peevish husk. ‘I can bear the dark. But not these endless days. I have always longed for tomorrow. For tomorrow I will understand a little more. I have always wanted to understand. Why I am here. Why the world is as it is. Why there is something, rather than nothing.'

'Lon' for tomorrow,' Mary echoed, seeking to comfort her.

'Yes. But you do not dream of the future, do you? For you there is only today. Here especially, with your Long Day and your Long Night, as if a whole year is made of one tremendous day.'

Overhead, a single bright star appeared.

Nemoto gasped. 'The first star since the spring. How marvellous, how beautiful, how fragile.' She settled back on her bundle of skins. 'You know, the stars here are the same - I mean the same as those that surround the world where I grew up, the Blue Earth. But the way they swim around the sky is not the same.' She was trying to raise her arm, perhaps to point, but could not. 'You have a different pole star here. It is somewhere in Leo, near the sky's equator. I cannot determine which… Your world is tipped over, you see, like Uranus, like a top lying on its side; that is how the Big Whack shaped it here. And so for six months, when your pole

points at the sun, you have endless light; and for six months endless dark… Do you follow me? No, I am sure you do not.' She coughed, and seemed to sink deeper into the skins. 'All my life I have sought to understand. I believe I would have pursued the same course whichever of our splintered worlds I had been born into. And yet, and yet -' She arched her back, and Mary laid her huge hands on Nemoto's forehead, trying to soothe her. 'And yet I die alone.'

Mary took her hand. It was delicate, like a child's. 'Not alone,' she said.

'Ah. I have you, don't I, Mary? I have a friend. That is something, isn't it? That is an achievement…' Nemoto tried to squeeze Mary's hand; it was the gentlest of touches.

And the sun, as if apologetically, slid beneath the horizon. Crimson light towered into the sky.

There are no books here. There is nothing like writing of any kind. And there is no art: no paintings on animal skins or cave walls, no tattoos, not so much as a dab of crushed rock on a child's face.

As a result, the Hams' world is a startlingly drab place, lacking art and story.

To me, a beautiful sunset is a comforting reminder of home, a symbol of renewal, a sign of hope for a better day tomorrow. But to the Hams, 1 believe, a sunset is just a sunset. But every sunset is like the first they have ever seen.

They are clearly aware of past and future, of change within their lives. They care for each other. They will show concern over another's wounds, and lavish attention on a sickly infant. They show pain, and fear, a great sense of loss when a loved one dies - and a deep awareness of their own mortality.

But they are quite without religion.

Think what that means. Every morning Mary must wake up, as alert and conscious as I am, and she must face the horror of life full in the face - without escape, without illusion, without consolation.

As for me, I have never abandoned my shining thread of hope that someday I will get out of here - without that I would fear for my sanity. But perhaps that is just my Homo sapiens illusion, my consolation.

Before the sun disappeared again, Mary had placed her friend in the ground, the ground of this Grey Earth.

The memory of Nemoto faded, as memories will.

But sometimes, sparked by the scent of the breeze that blew off the sea - a scent of different places - she would think of Nemoto, who had died far from home, but who had not died alone.

Huddle

A blue flash, a moment of searing pain. Madeleine Meacher was home.

She had fled the solar system at a time of war. The sun itself had been under attack, from interstellar bandits called the Crackers. Thanks to Einstein, she had arrived home from the stars a hundred thousand years later.

She waited in trepidation for data.

His birth was violent. He was expelled from warm red-dark into black and white and cold, a cold that dug into his flesh immediately.

He hit a hard white surface and rolled onto his back.

He tried to lift his head. He found himself inside a little fat body, grey fur soaked in a ruddy liquid that was already freezing.

Above him there was a deep violet-blue speckled with points of light, and two grey discs. Moons. The word came from nowhere, into his head. Moons, two of them.

There were people with him, on this surface. Shapeless mounds of fat and fur that towered over him. Mother. One of them was his mother. She was speaking to him, gentle wordless murmurs.

He opened his mouth, found it clogged. He spat. Air rushed into his lungs, cold, piercing.

Tenderly his mother licked mucus off his face.

But now the great wind howled across the ice, unimpeded. It grew dark. A flurry of snow fell across him.

His mother grabbed him and tucked him into a fold of skin under her belly. He crawled onto her broad feet, to get off the ice. There was bare skin here, thick with blood vessels, and he

' snuggled against its heat gratefully. And there was a nipple, from which he could suckle.

He could feel the press of other people around his mother, adding their warmth.

He slept, woke, fed, slept again, barely disturbed by his mother's shuffling movements.

The sharp urgency of the cold dissipated, and time dissolved.

He could hear his mother's voice, booming through her big jelly. She spoke to him, murmuring; and, gradually, he learned to reply, his own small voice piping against the vast warmth of her stomach. She told him her name - No-sun - and she told him about the world: people and ice and rock and food. 'Three winters: one to grow, one to birth, one to die…' Birth, sex and death. The world, it seemed, was a simple place.

The cold and wind went on, unrelenting. Perhaps it would go on forever.

She told him stories, about human beings.

'… We survived the Collision,' she said. 'We are surviving now. Our purpose is to help others. We will never die…' Over and over.

To help others. It was good to have a purpose, he thought. It lifted him out of the dull ache of the cold, that reached him even here. He slept as much as he could.

. There were no ships to greet her, no signals from the inner system.

The sun was still shining, though, just as it always had.

Did that mean the Crackers had indeed been repulsed? Or had the sun simply found some new equilibrium, after their meddling?

Madeleine found three giant comets, swooping through the heart of the system. Another was on its way, sailing in from the Oort cloud, due in a century or two.

She sought out Earth.

Too far to make out details. There was oxygen in the air, though. Was that a good sign? Oxygen was reactive. The rocks would rust, taking the oxygen out of the air. Unless there was an agency to replace it. Such as life. If all the life had been scraped off the Earth, how long would it take the oxygen to disappear?

Was Earth alive or dead?

She didn't know. The alien Gaijin were her allies. They had taken her to the stars and back, in search of Reid Malenfant. But they couldn't tell her what had become of Earth.

The Earth seemed bright, white. A pale-white dot. Silent. She sailed towards the inner system, black dread thickening.

No-sun pulled her broad feet out from under him, dumping him onto the hard ice. It was like a second birth. The ice was dazzling white, blinding him. Spring.

The sun was low to his right, its light hard and flat, and the sky was a deep blue-black over a landscape of rock and scattered scraps of ice. On the other horizon, he saw, the land tilted up to a range of mountains, tall, blood-red in the light of the sun. The mountains were to the west of here, the way the sun would set; to the east lay that barren plain; it was morning, here on the ice.

East. West. Morning. Spring. The words popped into his head, unbidden.

There was an austere beauty about the world. But nothing moved in it, save human beings.

He looked up at his mother. No-sun was a skinny wreck; her fur hung loose from her bones. She had spent herself in feeding him through the winter, he realized.

He tried to stand. He slithered over the ice, flapping ineffectually at its hard surface, while his mother poked and prodded him.

There was a sound of scraping.

The people had dispersed across the ice. One by one they were starting to scratch at the ice with their long teeth. The adults were gaunt pillars, wasted by the winter. There were other children, little fat balls of fur like himself.

He saw other forms on the ice: long, low, snow heaped up against them, lying still. Here and there fur showed, in pathetic tufts.

'What are they?'

His mother glanced apathetically. 'Not everybody makes it.' 'I don't like it here.'

She laughed, hollowly, and gnawed at the ice. 'Help me.'

After an unmeasured time they broke through the ice, to a dark liquid beneath. Water.

When the hole was big enough, No-sun kicked him into it.

He found himself plunged into dark fluid. He tried to breathe, and got a mouthful of chill water. He panicked, helpless, scrabbling. Dark shapes moved around him.

A strong arm wrapped around him, lifted his head into the air. He gasped gratefully.

He was bobbing, with his mother, in one of the holes in the

ice. There were other humans here, their furry heads poking out of the water, nostrils flaring as they gulped in air. They nibbled steadily at the edges of the ice.

'Here's how you eat,' No-sun said. She ducked under the surface, pulling him down, and she started to graze at the underside of the ice, scraping at it with her long incisors. When she had a mouthful, she mushed it around to melt the ice, then squirted the water out through her big, overlapping molars and premolars, and munched the remnants.

He tried to copy her, but his gums were soft, his teeth tiny and ineffective.

I? 'Your teeth will grow,' his mother said. 'There's algae growing in the ice. See the red stuff?'

He saw it, like traces of blood in the ice. Dim understandings stirred.

'Look after your teeth.'

'What?'

'Look at him.'

A fat old man sat on the ice, alone, doleful. 'What's wrong with him?'

'His teeth wore out.' She grinned at him, showing incisors and big canines.

He stared at the old man.

The long struggle of living had begun.

Later, the light started to fade from the sky: purple, black, stars. Above the western mountains there was a curtain of light, red and violet, ghostly, shimmering, semi-transparent.

He gasped in wonder. 'It's beautiful.'

She grinned. 'The night dawn.'

But her voice was uneven; she was being pulled under the water by a heavy grey-pelted body. A snout protruded from the water and bit her neck, drawing blood. 'Ow,' she said. 'Bull -'

He was offended. 'Is that my father?'

'The Bull is everybody's father.'

'Wait,' he said. 'What's my name?'

She thought for a moment. Then she pointed up, at the sky burning above the mountains like a rocky dream. 'Night-Dawn,' she said.

And, in a swirl of bubbles, she slid into the water, laughing.

Triton was gone.

Neptune had a new ring, of chunks of rock and ice that was slowly dispersing. Because of its retrograde orbit, Triton had been doomed anyhow: to spiral closer to Neptune, to be broken up by the increasing tides. But not yet; not for hundreds of millions of years.

The asteroids were - sparse. They had been broken up for their resources, sailed away, destroyed in wars. The solar system, it seemed, had been overrun, mined out, just like so many others.

Even so, somehow, in her heart of hearts, Madeleine never thought it would happen here.

Night-Dawn fed almost all the time. So did everybody else, to prepare for the winter, which was never far from anyone's thoughts. The adults co-operated dully, bickering.

Sometimes one or other of the men fought with the Bull. The contender was supposed to put up a fight for a while - collect scars, maybe even inflict a few himself - before backing off and letting the Bull win.

The children, Night-Dawn among them, fed and played and staged mock fights in imitation of the Bull. Night-Dawn spent most of his time in the water, feeding on the thin beds of algae, the krill and fish. He became friendly with a girl called Frazil. In the water she was sleek and graceful.

Night-Dawn learned to dive.

As the water thickened around him he could feel his chest collapse against his spine, the thump of his heart slow, his muscles grow more sluggish as his body conserved its air. He learned to enjoy the pulse of the long muscles in his legs and back, the warm satisfaction of cramming his jaw with tasty krill. It was dark under the ice, even at the height of summer, and the calls of the humans echoed from the dim white roof.

He dived deep, reaching as far as the bottom of the water, a hard invisible floor. Vegetation clung here, and there were a few fat, reluctant fishes.

And the bones of children.

Some of the children did not grow well. When they died, their parents delivered their misshapen little bodies to the water, crying and cursing the sunlight.

His mother told him about the Collision.

Something had come barrelling out of the sky, and the Moon

- one or other of them - had leapt out of the belly of the Earth. The water, the air itself was ripped from the world. Giant waves reared in the very rock, throwing the people high, crushing them or burning them or drowning them.

But they - the people of the ice - survived all this in a deep hole in the ground, No-sun said. They had been given a privileged shelter, and a mission: to help others, less fortunate, after the calamity.

They had spilled out of their hole in the ground, ready to help. Most had frozen to death, immediately.

They had food, from their hole, but it did not last long; they had tools to help them survive, but they broke and wore out and shattered. People were forced to dig with their teeth in the ice, as Night-Dawn did now.

Their problems did not end with hunger and cold. The thinness of the air made the sun into a new enemy.

Many babies were born changed. Most died. But some survived, better suited to the cold. Hearts accelerated, life shortened. People changed, moulded like slush in the warm palm of the sun.

Night-Dawn was intrigued by the story. But that was all it was: a story, irrelevant to Night-Dawn's world, which was a plain of rock, a frozen pond of ice, people scraping for sparse mouthfuls of food. How, why, when: the time for such questions, on the blasted face of Earth, had passed.

And yet they troubled Night-Dark, as he huddled with the others, half-asleep.

One day - in the water, with the soft back fur of Frazil pressed against his chest - he felt something stir beneath his belly. He wriggled experimentally, rubbing the bump against the girl.

She moved away, muttering. But she looked back at him, and he thought she smiled. Her fur was indeed sleek and perfect.

He showed his erection to his mother. She inspected it gravely; it stuck out of his fur like a splinter of ice.

'Soon you will have a choice to make.'

'What choice?'

But she would not reply. She waddled away and dropped into the water.

The erection faded after a while, but it came back. More and more frequently, in fact. He showed it to Frazil.

Her fur ruffled up into a ball. 'It's small,' she said dubiously. 'Do you know what to do?'

'I think so. I've watched the Bull.' 'All right.'

She turned her back, looking over her shoulder at him, and reached for her genital slit.

But now a fat arm slammed into his back. He crashed to the ice, falling painfully on his penis, which shrank back immediately.

It was the Bull, his father. The huge man was a mountain of flesh and muscle, silhouetted against a violet sky. He hauled out his own penis from under his greying fur. It was a fat, battered lump of flesh. He waggled it at Night-Dawn. 'I'm the Bull. Not you. Frazil is mine.'

Now Night-Dawn understood the choice his mother had set out before him.

He felt something gather within him. Not anger: a sense of wrongness.

'I won't fight you,' he said to the Bull. 'Humans shouldn't behave like this.'

The Bull roared, opened his mouth to display his canines, and turned away from him.

Frazil slipped into the water, to evade the Bull. Night-Dawn was left alone, frustrated, baffled.

As winter approached, a sense of oppression, of wrongness, gathered over Night-Dawn, and his mood darkened like the days.

People did nothing but feed and breed and die.

He watched the Bull. Behind the old man's back, even as he bullied and assaulted the smaller males, some of the other men approached the women and girls and coupled furtively. It happened all the time. Probably the group would have died out long ago if only the children of the Bull were permitted to be conceived.

The Bull was an absurdity, then, even as he dominated the little group. Night-Dawn wondered if the Bull was truly his father.

… Sometimes at night he watched the flags of night dawn ripple over the mountains. He wondered why the night dawns should come there, and nowhere else.

Perhaps the air was thicker there. Perhaps it was warmer beyond the mountains; perhaps there were people there.

But there was little time for reflection.

It got colder, fiercely so.

As the ice holes began to freeze over, the people emerged reluctantly from the water, standing on the hardening ice.

In a freezing hole, a slush of ice crystal clumps would gather, His mother called that frazil. Then, when the slush had condensed to form a solid surface, it took on a dull matte appearance - grease ice. The waves beneath the larger holes made the grease ice gather in wide, flat pancakes, with here and there stray, protruding crys-tals, called congelation. At last, the new ice grew harder and compressed with groans and cracks, into pack ice. There were lots of words for ice.

And after the holes were frozen over the water - and their only food supply - was cut off, for six months.

When the blizzards came, the huddle began.

The adults and children - some of them little fat balls of fur barely able to walk - came together, bodies pressed close, enveloping Night-Dawn in a welcome warmth, the shallow swell of their breathing pressing against him.

The snow, flecked with ice splinters, came at them horizontally. Night-Dawn tucked his head as deep as he could into the press of bodies, keeping his eyes squeezed closed.

Night fell. Day returned. He slept, in patches, standing up.

Sometimes he could hear people talking. But then the wind rose to a scream, drowning human voices.

The days wore away, still shortening, as dark as the nights.

The group shifted, subtly. People were moving around him. He got colder. Suddenly somebody moved away, a fat man, and Night-Dawn found himself exposed to the wind. The cold cut into him, shocking him awake.

He tried to push back into the mass of bodies, to regain the warmth.

The disturbance spread like a ripple through the group. He saw heads raised, eyes crusted with sleep and snow. With the group's tightness broken, a mass of hot air rose from the compressed bodies, steaming, frosting, bright in the double-shadowed Moonlight.

Here was No-sun, blocking his way. 'Stay out there. You have to take your turn.' 'But it's cold.' She turned away.

He tucked his head under his arm and turned his back to the wind. He stood the cold as long as he could.

Then, following the lead of others, he worked his way around the rim of the group, to its leeward side. At least here he was sheltered. And after a time more came around, shivering and iced up from their time to windward, and gradually he was encased once more in warmth.

Isolated on their scrap of ice, with no shelter save each other's bodies from the wind and snow, the little group of humans huddled in silence. As they took their turns at the windward side, the group shifted slowly across the ice, a creeping mat of fur.

Sometimes children were born onto the ice. The people pushed around closely, to protect the new-born, and its mother would tuck it away into the warmth of her body. Occasionally one of them fell away, and remained where she or he lay, as the group moved on.

This was the huddle: a black disc of fur and flesh and human bones, swept by the storms of Earth's unending winter.

A hundred thousand years after the Collision, all humans had left was each other.

Mars was a deserted ice ball, as it had always been.

Venus was choked by acid clouds, its surface glowing red hot.

Mercury was, simply, gone. She smiled at that. Mercury had been the last refuge of mankind. Perhaps humanity persisted, somewhere out there, beyond.

The Moon appeared restored: the craters, the great lava seas, the gleaming, ancient highlands. As if life had never touched its ancient face. But in the telescopic viewers she could see the traces of mankind, persisting even now. Abandoned dwellings, clinging to crater walls. Canals cut from crater to crater. Even water marks in some of the smaller craters, like drained bath tubs. Air, frozen out in the permanent shadows of the poles.

And to Earth, at last, she turned.

Spring came slowly.

Dwarfed by the desolate, rocky landscape, bereft of shelter, the humans scratched at their isolated puddle of ice, beginning the year's feeding.

Night-Dawn scraped ice from his eyes. He felt as if he were waking from a year-long sleep. This was his second spring, and it would be the summer of his manhood. He would father children,

teach them and protect them through the coming winter. Despite the depletion of his winter fat, he felt strong, vigorous.

He found Frazil. They stood together, wordless, on the thick early-spring ice.

Somebody roared in his ear, hot foul breath on his neck.

It was, of course, the Bull. The old man would not see another winter; his ragged fur lay loose on his huge, empty frame, riven by the scars of forgotten, meaningless battles. But he was still immense and strong, still the Bull.

Without preamble, the Bull sank his teeth into Night-Dawn's neck, and pulled away a lump of flesh, which he chewed noisily.

Night-Dawn backed away, appalled, breathing hard, blood running down his fur.

Frazil and No-sun were here with him.

'Challenge him,' No-sun said.

'I don't want to fight.'

'Then let him die,' Frazil said. 'He is old and stupid. We can couple despite him.' There was a bellow. The Bull was facing him, pawing at the ice with a great scaly foot.

T don't wish to fight you,' Night-Dawn said.

The Bull laughed, and lumbered forward, wheezing.

Night-Dawn stood his ground, braced his feet against the ice, and put his head down.

The Bull's roar turned to alarm, and he tried to stop; but his feet could gain no purchase.

His mouth slammed over Night-Dawn's skull. Night-Dawn screamed as the Bull's teeth grated through his fur and flesh to his very bone.

They bounced off each other. Night-Dawn felt himself tumbling back, and finished up on his backside on the ice. His chest felt crushed; he laboured to breathe. He could barely see through the blood streaming into his eyes.

The Bull was lying on his back, his loose belly hoisted towards the violet sky. He was feeling his mouth with his fingers.

He let out a long, despairing moan.

No-sun helped Night-Dawn to his feet. 'You did it. You smashed his teeth, Night-Dawn. He'll be dead in days.' ‘I didn't mean to -'

His mother leaned close. 'You're the Bull now. You can couple with who you like. Even me, if you want to.' '… Night-Dawn.'

Here came Frazil. She was smiling. She turned her back to him, bent over, and pulled open her genital slit. His penis rose in response, without his volition.

He coupled with her quickly. He did it at the centre of a circle of watching, envious, calculating men. It brought him no joy, and they parted without words.

He avoided the Bull until the old man had starved to death, gums bleeding from ice cuts, and the others had dumped his body into a water hole.

For Night-Dawn, everything was different after that.

He was the Bull. He could couple with who he liked. He stayed with Frazil. But even coupling with Frazil brought him little pleasure.

One day he was challenged by another young man called One-Tusk, over a woman Night-Dawn barely knew, called Ice-Cloud.

'Fight, damn you,' One-Tusk lisped.

'We shouldn't fight. I don't care about Ice-Cloud.'

One-Tusk growled, pursued him for a while, then gave up. Night-Dawn saw him try to mate with one of the women, but she laughed at him and pushed him away.

Frazil came to him. 'We can't live like this. You're the Bull. Act like it.'

'To fight, to eat, to huddle, to raise children, to die… There must be more, Frazil.' She sighed. 'Like what?' 'The Collision. Our purpose.'

She studied him. 'Night-Dawn, listen to me. The Collision is a pretty story. Something to make us feel better, while we suck scum out of ice.'

That was Frazil, he thought fondly. Practical. Unimaginative. 'Anyhow,' she said, 'where are the people we are supposed to help?'

He pointed to the western horizon: the rising ground, the place beyond the blue-grey mountains. 'There, perhaps.'

The next day, he called together the people. They stood in ranks on the ice, their fur spiky, rows of dark shapes in an empty landscape.

'We are all humans,' he said boldly. 'The Collision threw us here, onto the ice.' Night-Dawn pointed to the distant mountains.

'We must go there. Maybe there are people there. Maybe they are waiting for us, to huddle with them.' Somebody laughed.

'Why now?' asked the woman, Ice-Cloud.

'If not now, when? Now is no different from any other time, on the ice. I'll go alone if I have to.'

People started to walk away, back to the ice holes.

All, except for Frazil and No-sun and One-Tusk.

No-sun, his mother, said, 'You'll die if you go alone. I suppose it's my fault you're like this.'

One-Tusk said, 'Do you really think there are people in the mountains?'

'Please don't go,' Frazil said. 'This is our summer. You will waste your life.'

'I'm sorry,' he said.

'You're the Bull. You have everything we can offer.' 'It's not enough.'

He turned his back, faced the mountains and began to walk. He walked past the droppings and blood smears and scars in the ice, the evidence of humans. He stopped and looked back.

The people had lined up to watch him go - all except for two men who were fighting viciously, no doubt contesting his succession, and a man and woman who were coupling vigorously. And except for Frazil and No-sun and One-Tusk, who padded across the ice after him.

He turned and walked on, until he reached bare, untrodden ice.

After the first day of walking, the ice got thinner.

At last they reached a place where there was no free water beneath, the ice firmly bonded to a surface of dark rock. And when they walked a little further, the rock bed itself emerged from beneath the ice.

Night-Dawn stared at it in fascination and fear. It was black and deep and hard under his feet, and he missed the slick compressibility of ice.

The next day they came to another ice pool: smaller than their own, but a welcome sight nonetheless. They ran gleefully onto its cool white surface. They scraped holes into the ice, and fed deeply.

They stayed a night. But the next day they walked onto rock again, and Night-Dawn could see no more ice ahead.

The rock began to rise, becoming a slope.

They had no food. Occasionally they took scrapes at the rising stone, but it threatened to crack their teeth.

At night the wind was bitter, spilling off the flanks of the mountains, and they huddled as best they could, their backs to the cold, their faces and bellies together.

'We'll die,' One-Tusk would whisper.

'We won't die,' Night-Dawn said. 'We have our fat.'

'That's supposed to last us through the winter,' hissed No-sun.

One-Tusk shivered and moved a little more to leeward. 'I wished to father a child,' he said. 'By Ice-Cloud. I could not. Ice-Cloud mocked me. After that nobody would couple with me.'

'Ice-Cloud should have come to you, Night-Dawn. You are the Bull,' No-sun muttered.

'I'm sorry,' Night-Dawn said to One-Tusk. 'I have fathered no children yet. Not every coupling -'

One-Tusk said, 'Do you really think it will be warm in the mountains?'

'Try to sleep now,' said Frazil sensibly.

They were many days on the rising rock. The air grew thinner. The sky was never brighter than a deep violet blue.

The mountains, at last, grew nearer. On clear days the sun cast long shadows that reached out to them.

Night-Dawn saw a gap in the mountains, a cleft through which he could sometimes see a slice of blue-violet sky. They turned that way, and walked on.

Still they climbed; still the air thinned.

They came to the pass through the mountains. It was a narrow gully. Its mouth was broad, and there was broken rock, evidently cracked off the gully sides.

Night-Dawn led them forward.

Soon the walls narrowed around him, the rock slick with hard grey ice. His feet slipped from under him, and he banged knees and hips against bone-hard ice. He was not, he knew, made for climbing. And besides, he had never been surrounded before, except in the huddle. He felt trapped, confined.

He persisted, doggedly.

His world closed down to the aches of his body, the gully around him, the search for the next handhold… . The air was hot.

He stopped, stunned by this realization.

With renewed excitement, he lodged his stubby fingers in crevices in the rock, and hauled himself upwards. At last the gully grew narrower.

He reached the top and dragged himself up over the edge, panting, fur steaming.

… There were no people here.

He was standing at the rim of a great bowl cut into the hard black rock. And at the base of the bowl was a red liquid, bubbling slowly. Steam gathered in great clouds over the bubbling pool, laced with yellowish fumes that stank strongly. It was a place of rock and gas, not of people.

Frazil came to stand beside him. She was breathing hard, and her mouth was wide open, her arms spread wide, to shed heat.

They stood before the bowl of heat, drawn by some ancient imperative to the warmth, and yet repelled by its suffocating thickness.

'The Collision,' she said.

'What?'

'Once, the whole world was covered with such pools. Rock, melted by the great heat of the Collision.' 'The Collision is just a story, you said.' She grunted. 'I've been wrong before.'

His disappointment was crushing. 'Nobody could live here. There is warmth, but it is poisonous.' He found it hard even to think, so huge was his sense of failure.

He stood away from the others and looked around.

Back the way they had come, the uniform-hard blackness was broken only by scattered islands of grey-white: ice pools, Night-Dawn knew, like the one he had left behind.

Turning, he could see the sweep of the mountains clearly: he was breaching a great inward-curving wall, a great complex string of peaks that spread from horizon to horizon, gaunt under the blue-purple sky.

And ahead of him, ice had gathered in pools and crevasses at the feet of the mountains, lapping against the rock walls as if frustrated - save in one place, where a great tongue of ice had broken through. Glacier, he thought.

He saw that they could walk around the bowl of bubbling liquid rock and reach the head of the glacier, perhaps before night fell, and then move on, beyond these mountains. Hope sparked. Perhaps what he sought lay there.

'I'm exhausted,' No-sun said, a pillar of fur slumped against a heap of rock. 'We should go back.'

Night-Dawn, distracted by his plans, turned to her. 'Why?'

'We are creatures of cold. Feel how you burn up inside your fat. This is not our place…'

'Look,' breathed One-Tusk, coming up to them.

He was carrying a rock he'd cracked open. Inside there was a thin line of red and black. Algae, perhaps. And, in a hollow in the rock, small insects wriggled, their red shells bright.

Frazil fell on the rock, gnawing at it eagerly.

The others quickly grabbed handfuls of rocks and began to crack them open.

They spent the night in a hollow at the base of the glacier.

In the morning they clambered up onto its smooth, rock-littered surface. The ice groaned as it was compressed by its forced passage through the mountains, which towered above them to either side, blue-grey and forbidding.

At the glacier's highest point, they saw that the river of ice descended to an icy plain. And the plain led to another wall of mountains, so remote it was almost lost in the horizon's mist.

'More walls,' groaned One-Tusk. 'Walls that go on forever.'

'I don't think so,' said Night-Dawn. He swept his arm along the line of the distant peaks, which glowed pink in the sun. 'I think they curve. You see?'

'I can't tell,' muttered No-sun, squinting.

With splayed toes on the ice, Night-Dawn scraped three parallel curves - then, tentatively, he joined them up into concentric circles. 'Curved walls of mountains. Maybe that's what we're walking into,' he said. 'Like a ripples in a water hole.'

'Ripples, in rock?' Frazil asked sceptically.

'If the Collision stories are true, it's possible.'

No-sun tapped at the centre of his picture. 'And what will we find here?'

'I don't know.'

They rested a while, and moved on.

The glacier began to descend so rapidly they had some trouble keeping their feet. The ice here, under tension, was cracked, and there were many ravines.

At last they came to a kind of cliff, hundreds of times taller than Night-Dawn. The glacier was tumbling gracefully into the

ice plain, great blocks of it carving away. This ice sheet was much wider than the pool they had left behind, so wide, in fact, it lapped to left and right as far as they could see and all the way to the far mountains. Ice lay on the surface in great broken sheets, but clear water, blue-black, was visible in the gaps.

It was - together they found the word, deep in their engineered memories - it was a sea.

'Perhaps this is a circular sea,' One-Tusk said, excited. 'Perhaps it fills up the ring between the mountains.'

'Perhaps.'

They clambered down the glacier, caution and eagerness warring in Night-Dawn's heart.

There was a shallow beach here, of shattered stone. The beach was littered with droppings, black-and-white streaks, and half-eaten krill.

In his short life, Night-Dawn had seen no creatures save fish, krill, algae and humans. But this beach did not bear the mark of humans like themselves. He struggled to imagine what might live here.

Without hesitation, One-Tusk ran to a slab of pack ice, loosely anchored. With a yell he dropped off the end into the water. No-sun fluffed up her fur. 'I don't like it here -' Bubbles were coming out of the water, where One-Tusk had dived.

Night-Dawn rushed to the edge of the water.

One-Tusk surfaced, screaming, in a flurry of foam. Half his scalp was torn away, exposing pink raw flesh, the white of bone.

An immense shape loomed out of the water after him: Night-Dawn glimpsed a pink mouth, peg-like teeth, a dangling wattle, small black eyes. The huge mouth closed around One-Tusk's neck.

He had time for one more scream - and then he was gone, dragged under the surface again.

The thick, sluggish water grew calm; last bubbles broke the surface, pink with blood.

Night-Dawn and the others huddled together.

'He is dead,' Frazil said.

'We all die,' said No-sun. 'Death is easy.'

'Did you see its eyes?' Frazil asked.

'Yes. Human,' No-sun said bleakly. 'Not like us, but human.' 'Perhaps there were other ways to survive the Collision.'

No-sun turned on her son. 'Are we supposed to huddle with that, Night-Dawn?'

Night-Dawn, shocked, unable to speak, was beyond calculation. He explored his heart, searching for grief for loyal, confused One-Tusk.

They stayed on the beach for many days, fearful of the inhabited water. They ate nothing but scavenged scraps of crushed, half-rotten krill left behind by whatever creatures had lived here.

'We should go back,' said No-sun at last.

'We can't,' Night-Dawn whispered. 'It's already too late. We couldn't get back to the huddle before winter.'

'But we can't stay here,' Frazil said.

'So we go on.' No-sun laughed, her voice thin and weak. 'We go on, across the sea, until we can't go on any more.' 'Or until we find shelter,' Night-Dawn said. 'Oh, yes,' No-sun whispered. 'There is that.' So they walked on, over the pack ice.

This was no mere pond, as they had left behind; this was an ocean.

The ice was thin, partially melted, poorly packed. Here and there the ice was piled up into cliffs and mountains that towered over them; the ice hills were eroded, shaped smooth by the wind, carved into fantastic arches and spires and hollows. The ice was every shade of blue. And when the sun set its light filled the ice shapes with pink, red and orange.

There was a cacophony of noise: groans and cracks, as the ice moved around them. But there were no human voices, save their own: only the empty noise of the ice - and the occasional murmur, Night-Dawn thought, of whatever giant beasts inhabited this huge sea.

They walked for days. The mountain chain they had left behind dwindled, dipping into the mist of the horizon; and the chain ahead of them approached with stultifying slowness. He imagined looking down on himself, a small, determined speck walking steadily across this great, moulded landscape, working towards the mysteries of the centre.

Food was easy to find. The slushy ice was soft and easy to break through.

No-sun would walk only slowly now. And she would not eat. Her memory of the monster which had snapped up One-Tusk was

too strong. Night-Dawn even braved the water to bring her fish, but they were strange: ghostly-white creatures with flattened heads, sharp teeth. No-sun pushed them away, saying she preferred to consume her own good fat. And so she grew steadily more wasted.

Until there came a day when, waking, she would not move at all. She stood at the centre of a fat, stable ice floe, a pillar of loose flesh, rolls of fur cascading down a frame leached of fat.

Night-Dawn stood before her, punched her lightly, cajoled her.

'Leave me here,' she said. 'It's my time anyhow.'

'No. It isn't right.'

She laughed, and fluid rattled on her lungs. 'Right. Wrong. You're a dreamer. You always were. It's my fault, probably.'

She subsided, as if deflating, and fell back onto the ice.

He knelt and cradled her head in his lap. He stayed there all night, the cold of the ice seeping through the flesh of his knees.

In the morning, stiff with the cold, they took her to the edge of the ice floe and tipped her into the water, for the benefit of the creatures of this giant sea.

After more days of walking, the ice grew thin, the water beneath shallow.

Another day of this and they came to a slope of hard black rock, that pushed its way out of the ice and rose up before them.

The black rock was hard-edged and cold under Night-Dawn's feet, its rise unrelenting. As far as he could see to left and right, the ridge was solid, unbroken, with no convenient passes for them to follow, the sky lidded over by cloud.

They grasped each other's hands and pressed up the slope.

The climb exhausted Night-Dawn immediately. And there was nothing to eat or drink, here on the high rocks, not so much as a scrap of ice. Soon, even the air grew thin; he struggled to drag energy from its pale substance.

When they slept, they stood on hard black rock. Night-Dawn feared and hated the rock; it was an enemy, rooted deep in the Earth.

On the fourth day of this they entered the clouds, and he could not even see where his next step should be placed. With the thin, icy moisture in his lungs and spreading on his fur he felt trapped, as if under some infinite ice layer, far from any air hole. He struggled to breathe, and if he slept, he woke consumed by a thin panic. At such times he clung to Frazil and remembered who he was and

where he had come from and why he had come so far. He was a human being, and he had a mission that he would fulfil.

Then, one morning, they broke through the last ragged clouds.

Though it was close to midday the sky was as dark as he had ever seen it, a deep violet blue. The only clouds were thin sheets of ice crystals, high above. And - he saw, gasping with astonishment - there were stars shining, even now, in the middle of the sunlit day.

The slope seemed to reach a crest, a short way ahead of him. They walked on. The air was thin, a whisper in his lungs, and he was suspended in silence; only the rasp of Frazil's shallow breath, the soft slap of their footsteps on the rock, broke up the stillness.

He reached the crest. The rock wall descended sharply from here, he saw, soon vanishing into layers of fat, fluffy clouds.

And, when he looked ahead, he saw a mountain.

Far ahead of them, dominating the horizon, it was a single peak that thrust out of scattered clouds, towering even over their elevated position here, its walls sheer and stark. Its flanks were girdled with ice, but the peak itself was bare black rock - too high even for ice to gather, he surmised - perhaps so high it thrust out of the very air itself.

It must be the greatest mountain in the world.

And beyond it there was a further line of mountains, he saw, like a line of broken teeth, marking the far horizon. When he looked to left and right, he could see how those mountains joined the crest he had climbed, in a giant unbroken ring around that great, central fist of rock.

It was a giant rock ripple, just as he had sketched in the ice. Perhaps this was the centre, the very heart of the great systems of mountain rings and circular seas he had penetrated.

An ocean lapped around the base of the mountain. He could see that glaciers flowed down its heroic base, rivers of ice dwarfed by the mountain's immensity. There was ice in the ocean too -pack ice, and icebergs like great eroded islands, white, carved. Some manner of creatures were visible on the bergs, black and grey dots against the pristine white of the ice, too distant for him to make out. But this sea was mostly melted, a band of blue-black.

The slope of black rock continued below him - far, far onwards, until it all but disappeared into the misty air at the base of this bowl of land. But he could see that it reached a beach of some

sort, of shattered, eroded rock sprinkled with snow, against which waves sluggishly lapped.

There was a belt of land around the sea, cradled by the ring mountains, fringed by the sea. And it was covered by life, great furry sheets of it. From this height it looked like an encrustation of algae. But he knew there must be living things there much greater in scale than any he had seen before.

'… It is a bowl,' Frazil breathed.

'What?'

'Look down there. This is a great bowl, of clouds and water and light, on whose lip we stand. We will be safe down there, away from the rock and ice.'

He saw she was right. This was indeed a bowl - presumably the great scar left where one or other of the Moons had torn itself loose of the Earth, just as the stories said. And these rings of mountains were ripples in the rock, frozen as if ice.

He forgot his hunger, his thirst, even the lack of air here; eagerly they began to hurry down the slope.

The air rapidly thickened.

But his breathing did not become any easier, for it grew warm, warmer than he had ever known it. Steam began to rise from his thick, heavy fur. He opened his mouth and raised his nostril flaps wide, sucking in the air. It was as if the heat of this giant sheltering bowl was now, at the last, driving them back.

But they did not give up their relentless descent, and he gathered the last of his strength.

The air beneath them cleared further.

Overwhelmed, Night-Dawn stopped.

The prolific land around the central sea was divided into neat shapes, he saw now, and here and there smoke rose. It was a made landscape. The work of people.

Humans were sheltered here. It was a final irony, that people should find shelter at the bottom of the great pit dug out of the Earth by the world-wrecking Collision.

... And there was a colour to that deep, cupped world, emerging now from the mist. Something he had never seen before; and yet the word for it dropped into place, just as had his first words after birth.

'Green,' Frazil said.

'Green. Yes…'

He was stunned by the brilliance of the colour against the black

rock, the dull blue-grey of the sea. But even as he looked into the pit of warmth and air, he felt a deep sadness. For he already knew he could never reach that deep shelter, peer up at the giant green living things; this body which shielded him from cold would allow heat to kill him. Somebody spoke.

The crater was immense.

It must have been the worst impact since the end of the great bombardment that had greeted Earth's formation.

The Gaijin helped her understand.

This was nothing to do with the Cracker wars of the remote past. In the long ages since then, the twin suns of Alpha Centauri had come sailing by the solar system, making a closest approach of about three light years. That was more than two hundred thousand astronomical units, a long way out. The twin suns hadn't come close enough to interfere with the orbits of the planets, still less the sun itself. But they were close enough to disturb the comets, sleeping through their orbits in the Oort cloud, that great sparse fuzzy halo in the outer dark.

Because of Alpha's grazing approach, more than two hundred thousand giant comets would cross Earth's orbit over the next twenty million years. The Gaijin had no data on how many might strike the planet, or its Moon. This game of cosmic billiards was nothing to do with intelligence, nothing to do with war. It was just a matter of the random motion of the stars, whizzing around the Galaxy like molecules in a gas.

Even without predatory colonists, she thought, the universe is a dangerous place.

… Yes - but if we'd been left undisturbed, if not for these squabbling, colonizing Eeties, we would have figured out how to push the damn things away for ourselves.

Too late now. Damn, damn.

He cried out, spun around. Frazil was standing stock still, staring up.

There was a creature standing here. Like a tall, very skinny human.

It was a human, he saw. A woman. Her face was small and neat, and there was barely a drop of fat on her, save around the hips, buttocks and breasts. Her chest was small. She had a coat

of some fine fur - no, he realized with shock; she was wearing a false skin, that hugged her bare flesh tightly. She was carrying green stuff, food perhaps, in a basket of false skin. She was twice his height.

Her eyes were undoubtedly human, though, as human as his, and her gaze was locked on his face. And in her eyes, he read fear. Fear, and disgust.

He stepped forward. 'We have come to help you,' he said. 'Yes,' said Frazil. 'We have come far -'

The tall woman spoke again, but he could not understand her. Even her voice was strange - thin, emanating from that shallow chest. She spoke again, and pointed, down towards the surface of the sea, far below.

Now he looked more closely he could see movement on the beach. Small dots, moving around. People, perhaps, like this girl. Some of them were small. Children, running free. Many children.

The woman turned, and started climbing away from them, down the slope towards her world, carrying whatever she had gathered from these high banks. She was shaking a fist at them now. She even bent to pick up a sharp stone and threw it towards Frazil; it fell short, clattering harmlessly.

Madeleine made her home in the depths of the crater, where air pooled, thick.

A single Gaijin flower-ship stayed in orbit, in case she called. The Gaijin seemed prepared to wait forever. Sometimes she glimpsed it, at dawn, at sunset.

Madeleine's conditions were hardly primitive. She had the Gaijin lander, which served as a fine shelter. It was stocked with food-preparation technology; all she had to do was cram its hoppers full of vegetable material, once or twice a week. But she also had her garden, and the fruits and berries she gathered from the sparse trees here, and she drank exclusively water from the snow-melt streams. It pleased her to live as close to the Earth as she could.

She didn't go near the circular sea, though. There were creatures living in there she couldn't identify. Their sleek forms scarcely looked friendly. And she thought there were human-like creatures on the far side of the sea. She didn't approach them either.

It was a world of scale and depth, of perspective. She would lie on her porch and watch the waterfalls glimmering through the

air from the rocky walls, kilometres above, and gaze even beyond that, at the feathery tails of the great comets that swept across the sky.

Sometimes she saw creatures moving against the ice which lapped against the rim mountains, far above her. Her sensor packs, even at highest magnification, showed her only penguin-like creatures, waddling over the ice, huddling against ferocious winds. Perhaps they were indeed some remote descendants of penguins. Or even post-humans, gruesomely adapted to survive. She felt no temptation to seek them out. But their presence disturbed her.

The Moon's grey face was reassuringly familiar. The tide of life on that patient satellite had long receded, and the face of the Man was restored to patient watchfulness. Just as she was.

It was a vigil, Madeleine had decided.

Once, she'd read of an island called San Nicolas, off Los Angeles. Long before the coming of the Europeans, it had been inhabited by native Americans. But the settlement had collapsed, the numbers dwindling, one by one.

The last survivor was a woman who had lived on, in complete isolation, for eighteen years.

How had she spent her time? Had she watched for canoes that had never come, hoped to see the return of some last, desperate emigrants? Or had she simply savoured her memories, and waited?

She tried not to think too hard. What good would that do?

Madeleine Meacher was no vigil-keeper.

She grew restless, despite herself.

This wasn't her world, whether it belonged to the post-humans or not. Anyhow she had never been too good at sitting still.

She'd never forgotten her alternative plan, as she'd discussed with Malenfant. To travel on and on. Why the hell not?

But if she entered the Saddle Point network again, she might never come out. If so, she supposed, she'd never know about it.

She watched the sky, studying the changed stars. When the wind picked up, stirring her wispy hair, she went into her lander and prepared her evening meal.

The next day, she called the Gaijin down from the sky.

'I don't understand,' Frazil said.

Night-Dawn thought of the loathing he had seen in the strange woman's eyes. He saw himself through her eyes: squat, fat, waddling, as if deformed.

He felt shame. 'We are not welcome here,' he said.

'We must bring the others here,' Frazil was saying.

'And what then? Beg to be allowed to stay, to enter the warmth? No. We will go home.'

'Home? To a place where people live a handful of winters, and must scrape food from ice with their teeth? How can that compare to this?'

He took her hands. 'But this is not for us. We are monsters to these people. As they are to us. And we cannot live here.'

She stared into the pit of light and green. 'But in time, our children might learn to live there. Just as we learned to live on the ice.'

The longing in her voice was painful. He thought of the generations who had lived out their short, bleak lives on the ice. He thought of his mother, who had sought to protect him to the end; poor One-Tusk, who had died without seeing the people of the mountains; dear, loyal Frazil, who had walked to the edge of the world at his side.

'Listen to me. Let these people have their hole in the ground. We have a world. We can live anywhere. We must go back and tell our people so.'

She sniffed. 'Dear Night-Dawn. Always dreaming. But first we must eat, for winter is coming.'

'Yes. First we eat.'

They inspected the rock that surrounded them. There was green here, he saw now, thin traces of it that clung to the surface of the rock. In some places it grew away from the rock face, brave little balls of it no bigger than his fist, and here and there fine fur-like sproutings.

They bent, reaching together for the green shoots. The shadows lengthened. The sun was descending towards the circular sea, and one of Earth's two Moons was rising.