'We're definitely going to have to work on our game,' Luiz said. 'If we can't get the better of a tribe of rats, we could get into some serious trouble when we go up against the Outers.'

'No way,' Cash said. 'We're way better than any of those tweaks. They claim they're evolving into Homo superior, but we're already there. We're the real deal. When it comes to it, we'll kick their asses for sure.'

3.

East of Eden, Ganymede, occupied a narrow crevasse at the southeastern edge of the dark and cratered terrain of Galileo Regio. The floor and sides of the crevasse were insulated and pressure-sealed with layers of fullerene composite and aerogel, and it was roofed with the same material, and the roof was covered in two metres of stony material, excavated from a nearby crater, to provide protection from the drench of radiation from the outer edges of Jupiter's radio belts. There was a small industrial zone at the southern end of the crevasse, and the rest was a pastoral landscape: meadows and groves of olive and citrus trees punctuated with narrow ponds and marshes along the floor; pine woods with an understorey of ceanothus, choisya, bearberries, myrtles, and other flowering shrubs climbing the terraced walls. Public buildings and small villages of apartment blocks sat amongst the steep woods under tents of transparent polymer stretched between fullerene struts, like giant models of the compound eyes of insects or exotic and jewellike phytoplankton.

The settlement had been founded some fifty years ago by a group who believed that the other inhabitants of Jupiter's moons had grown too soft, too bourgeois. Although their home was pleasantly bucolic, East of Eden's citizens were austere and close-minded, keen on conformity, custom, and civic duty, and they prized the acquisition of scientific and philosophical knowledge and the virtues of artistic achievement above all else. They each spent several days a week helping to run the settlement's basic services and maintain its infrastructure, but as far as they were concerned their real work was scientific research without any clear aim or application beyond the gathering and cataloguing of esoteric knowledge for knowledge's sake, or the production of intricate sagas, operas, symphonies, plays, and other works of art. They had developed and refined new meditation techniques, revived the ancient black arts of psychoanalysis, tweaked decorative plants and animals, engaged in the study of abnormal mathematics and philosophy, worked in obscure corners of the sprawling tangle of theories left over from failed attempts to unify physics, and much else. And they spent at least as much time talking about their art and research as doing it, discussing strategies and plans with other members of art covens or research gangs, arguing with rivals in virtual workshops, even organising face-to-face conferences. Their government, a form of direct democracy similar to that of the city-states of Classical Greece or the early years of the Roman Republic, involved endless discussions, too. There were no elected representatives, no instant polls or referenda. Assemblies in which every citizen could debate and vote were held once a week in villages and once a month for matters concerning the whole city. Luxury was a crime; self-sacrifice a virtue. Everything that wasn't forbidden was compulsory.

As far as Macy Minnot was concerned, it was about as Utopian as an anthill. She'd moved to East of Eden three months ago, immediately after her defection. The government of Rainbow Bridge, Callisto had insisted on it. Officially, it was for her protection. Unofficially, as she well knew, the Callistans were eager to be rid of an inconvenient reminder of an embarrassing incident.

East of Eden had volunteered to take her in not out of charity or sympathy, but because it discharged an obscure debt of honour it had long owed Rainbow Bridge. She'd been assigned a counsellor, a vinegary old man named Ivo Teagarden, and had been given work as a general labourer in East of Eden's farms, but her access to its net was restricted, she was forbidden to travel outside its limits, and she couldn't shake the feeling that she was part prisoner, part zoological specimen. Nevertheless, she was determined to make the best of it. She'd poured her energy into making over the studio apartment she'd been assigned, in the village of Lot's Lot: laying and polishing a bamboo-wood floor, painting the walls different shades of green and pink and playing with the lighting, retiling the little wet room, growing herbs and chilli plants in pots on the flagstone patio, training a fig vine around the door. She told herself that she was settling into the first real home she'd ever had, but in her low moments the apartment seemed more like a cell, and East of Eden's inward-looking pocket Utopia a prison.

So far, she'd made few friends. Ivo Teagarden. The proprietor of her favourite cafe in Lot's Lot's refectory, Jon Ho. Sada Selene and her little gang of refuseniks. A nodding acquaintance with a couple of people who worked in the farm tunnels. Most citizens were frostily polite or indifferent; only a few went out of their way to express outright hostility. Chief amongst the latter was Jibril, a member of the self-styled Elohim transhumanism crew. Everyone else called them cosmo angels, because they used plastic surgery and trivial cuts to give themselves a weird stylised beauty and dabbled in all kinds of so-called mind-enhancing treatments, from colour therapy to tailored psycho-trophic viruses. They were also androgyne neuters, because they had the fantastically old-fashioned notion that higher consciousness could be achieved only in the complete absence of every form of base, animal sex. They took the names of angels, erased their former identities from public record, and spent their leisure time hanging around public places, preening and fluttering like minor aristocrats. Most had something to do with the performance arts. East of Eden's best fado singer was a cosmo angel; so were several of its leading microentertainers. Jibril was a virtuoso of psychoactive theatre, and Macy had been on the receiving end of yo's performances ever since she'd first arrived in East of Eden, from sarcastic remarks or mocking questions made in passing to confrontational diatribes about base human stock compromising East of Eden's aesthetic totality, or the pollution of its gestalt. And every encounter was on camera, and edited versions were dumped on East of Eden's net for the delectation and entertainment of anyone who wanted to watch.

Back in the training barracks of the R&R corps, Macy had once called out a woman who'd been bugging her and they'd fought to a standstill behind the mess block, honour even. But after she made the mistake of trying the same tactic with Jibril, standing up to the cosmo angel and telling yo that there were plenty of places where they could work out their differences, the confrontation, which had ended with Macy stalking away in disgust from Jibril's fluttering mime of outraged sensibility, had quickly became the most popular of all the cosmo angel's pieces. Ivo Teagarden explained that cosmo angels suffered from an advanced but harmless state of narcissism, and said that Macy should think of these encounters as a contribution towards Jibril's therapy and a way of enhancing her own standing in the community. Jon Ho told her it didn't much matter, because most people didn't follow psychoactive theatre these days. Only the gang of self-styled refusenik kids took Macy's side, albeit mainly for ideological reasons.

'Cosmo angels confuse evolution with a lifestyle choice,' Sada Selene told Macy. She was the oldest of the refuseniks, a lanky and intense girl of fifteen. 'What they do to themselves? It's about as radical as getting a tattoo. It's a mockery of all the wild and radical possibilities of true transhumanism. Something safe and codified, reinforced by constant self-policing. Which is just about typical of all that's wrong with this backwater, puritanical, head-in-the-sand place.'

'They pretend they're devoted to a high ideal, but they're really running away from their own true nature,' another refusenik said. 'Like nuns. You ever heard of nuns?'

'She's from Earth. It's crawling with all kinds of religious weirdos,' a third refusenik said. 'Green saints. They're a kind of nun, right?'

'Kind of,' Macy said.

'The point is,' Sada Selene said, 'the cosmo angels don't threaten the status quo. That's why the system tolerates them, and why it hates us. Because we want to take control of the course of human evolution. Because true transhumans are always in flux, evolving in a hundred different directions. No so-called Utopia can deal with that because by their very nature Utopias are static. They hate change because it's a direct challenge to their fantasy of perfection.'

Macy liked the refuseniks because they were pretty much the only people in East of Eden with whom she could have a straightforward conversation. But although they claimed to be rebels without a pause, they were really just a bunch of alienated kids going through a difficult phase. Despite all their noise about living outside the law and their open contempt for the settlement's claustrophobic codes and customs, they hadn't ever attempted to change them, and it was unlikely that their boasts about leaving the settlement when they attained majority would come to anything. They refused to participate in civic life, but they camped out in empty apartments, lived on dole yeast and whatever they could cadge from passers-by, breathed the settlement's air, drank its water, and used its net. Still, they were bright and challenging, and they supported Macy because she was their enemy's enemy. They posted favourable comments about her on Jibril's site, and told her that she could always count on them if she got into trouble.

Early one evening, Macy was sitting at the counter of Jon Ho's cafe when she saw Jibril and two of yo's acolytes coming towards her. The cafe was at one end of the refectory terrace that occupied the top of the biggest apartment block of Lot's Lot, with views through the hexagonal panes of the village's tent towards pine woods on the other side of the crevasse. A nice enough prospect, although the trees were dwarfed, no more than five or six metres high, and they were just a couple of hundred metres away, squatting under the grey-blue vault of the roof. It reminded Macy of the room she'd shared with Jax Spano during the brief spring of their love back in Pittsburgh: if you stood in the centre you could touch the walls on either side, not just with your fingertips but with the palms of your hands. The cafe was small, too. Nicely compact. A short counter topped with split bamboo polished to a mirror finish, a bench long enough for six customers, and a hissing steel coffee machine that Jon Ho had built from a design three centuries old.

The coffee wasn't exactly coffee - coffee bushes took up too much space in farm tunnels, so the Outers generally grew a species of moss tweaked to produce oily caffeine-rich nodules - but it was the best Macy had found since she'd left Earth, and Jon conjured up tasty snacks on a little hotplate and allowed customers to keep a bottle of their favourite liqueur or spirit behind the counter. He'd worked a spell as a ship's engineer, was more widely travelled and more tolerant than most of East of Eden's citizens. He liked to listen to Macy's stories about life on Earth, and she liked to talk to him about tweaking strains of moss to improve the quality of their coffee; the art of making minuscule metabolic changes to ensure an exact balance of dozens of different flavonoids, alcohols, aldehydes, and essential oils was very like adjusting the balance of microorganisms to produce the sweetest, liveliest mud.

Jon was telling Macy about his latest attempt to produce a strain that would mimic the mellow flavour of Sumatra Mandheling when she saw the three cosmo angels threading their way through benches and tables, tubs of mosses and ferns and flowers, and cafes and vending stalls. Past a man and a woman leaning towards each other over a chess board, a man staring at figures tumbling through the glow of a memo space, a group of children learning how to make bread at a table outside the bake shop, squealing and chattering as they slapped and pummelled gobs of dough.

Jibril saying loudly, 'Can you really find the face of God in an irrational number?'

Macy knew at once that the cosmo angel had somehow found out about the Church of the Divine Regression and she stood up as adrenalin surged into her blood. Fight or flight. Dismay and anger.

'Please, help me understand,' the cosmo angel said. 'I know that the string of digits after the decimal point in pi is infinite, with no set of consecutive digits repeating itself indefinitely. But even if there was a complete description of the universe hidden somewhere inside, surely you'd need an infinite amount of time to unravel it. And as for finding God-'

'I'm not going to waste my time saying anything at all to you,' Macy said.

'But I'm genuinely interested,' Jibril said, blocking Macy's way as she attempted to push past.

The cosmo angel was two and a half metres tall, slender as a reed, and as usual dressed in a minimum of clothing, short-shorts and sandals and a bandolier belt, so as to best display yo's poreless white skin, yo's gallery of tattoos, the iridescent scales splashed on yo's chest. Yo's green and gold eyes glittered above razor-ridged cheekbones. The two acolytes, equally tall and slender, loomed over Macy, hemmed her in. A drone hung above, its underslung camera aimed straight at her.

'What kind of god were you looking for?' Jibril said. 'The white-bearded patriarch of old? Or someone in your image?'

'Heaven forbid,' one of the acolytes said.

'No, we must try to be charitable,' Jibril said. 'Still, the idea of any kind of god in Macy Minnot's image is rather distasteful.'

Jon Ho asked the cosmo angels if they were going to let his customer leave in a peaceable manner and Macy told him she didn't need his help and set her hands flat on the tops of the stools either side of her, pushed straight up in the light gravity, and sat on the counter and swivelled and stepped down on the other side.

'A wide-hipped, spraddle-legged chimpanzee,' Jibril called out as Macy walked away. 'It doesn't really satisfy any description of the creator of the universe, does it?'

The next morning, Jibril and yo's little coven were waiting for Macy at the entrance to the pedestrian subway that connected East of Eden to its cut-and-cover farm tunnels. The two acolytes recited numbers in sing-song unison while Jibril loudly asked Macy if she really thought that God would let Herself be uncovered by simple arithmetical tricks. Macy walked straight past with her fists balled in the pockets of her jerkin, ignoring the drone that kept pace with her. But the cosmo angels were there the next day, too. Asking her if she was plotting to spread the good word here and turn everyone into zombies searching for the secret of the universe in the entrails of an irrational number.

She refused to give them anything, not so much as a word or a cross-grained look. They put the footage up on their site anyway.

'You shouldn't take it personally,' Ivo Teagarden told her. 'As far as Jibril is concerned, you're raw material for yo's art.'

'Dragging up a life I left long ago is pretty personal.'

Macy had dreamed about the church the previous night. The cluster of trailers hunched around the old missile silo in the tawny light of one of the dust storms that blew out of the sere and empty desert of the ruined prairie circled all around. The stacked levels of servers and drives of the ancient and vast parallel computers in the silo, each level floored with steel mesh and crowded with cased racks of circuitry knitted together by neat runs of colour-coded cabling and fat grey arteries of optical cabling, shuddering in the thunderous vibration of the fans that kept them from overheating as they ground through endless calculations.

Macy's first job, after she and her mother had joined the church, had been to clean the server stacks; despite the seals, dust constantly infiltrated the silo and would quickly cause breakdowns and seizures if it wasn't vacuumed up. Later, Macy had graduated to the first level of prayerful exploration, flying across virtual landscapes created by simple arithmetical transformations of pi's infinite, divine regression. These regions had already been thoroughly explored, but they were useful for indoctrination and training, preparing the acolytes for higher levels such as the Fields of Forty, where Macy's mother flew down fractal branches spewed by transformation functions based on ratios between fundamental physical properties of light and mass and gravity that mirrored, so it was taught and so it was believed, the deep structure of the universe created by a mathematical God whose presence might yet lurk in His creation.

Day after day, year after year, the holy mathenauts flew down virtual renderings generated by complex transformations of pi's regression, searching for non-random spoor that might be the footprints or fingerprints of the Creator with a fanaticism that Macy had found ever more futile and claustrophobic as she grew older and her mother, by now a holy creature starveling thin and half-crazed from spending eighteen hours a day searching the divine regression, drew away from her and the rest of the real world.

Macy had left that life behind when she had run away. Left behind her mother and the only people she had known. She wouldn't have it back.

'Perhaps you could sit down with Jibril,' Ivo Teagarden suggested.

'Settle your differences face to face.'

'Jibril and its - sorry, yo's crew would video it and put it up on the net with demeaning little comments.'

'Then video them videoing you and post it. Make your own art that critiques Jibril's.'

'I'll think about it,' Macy said.

The old man meant well, but he thought that Macy could think like an Outer. She couldn't. She was a stranger in a strange land. Trying to imagine the long and possibly endless exile that stretched ahead gave her a strange, vertiginous feeling. A scary-bad rush in the pit of her stomach that made her realise just exactly what she'd gotten herself into: year after year of breathing canned air, the low-grade but everpresent fear of a blowout or some other sudden and comprehensive disaster, cramped horizons and closed spaces. Living with strangers who had nothing in common with her. Strangers who sometimes seemed barely human.

The next day, one of her rest days, she wandered over to the neighbouring apartment block, where a green market was being held. She was buying peppermint tea-moss from a woman who grew it in one of the little gardens terraced up the side of the crevasse when she saw a drone hanging above the neighbouring flower stall. And there was Jibril, stalking down the aisle with yo's two acolytes following close behind.

'I have a question,' Jibril said loudly, and with a flourish raised a laser pen above yo's shaven and tattooed head and conjured in the air the polychrome fishscales of one of the simpler inscapes of pi. 'Can you show me where God is in this picture?'

When Macy turned on her heel and set off in the other direction, Jibril made the mistake of chasing after her and trying to stop her by grabbing hold of one of her arms. Macy swung around, her anger sudden and bright and fierce, and struck the cosmo angel in the chest with the heel of her hand and said, 'You want a show? How about having it out with me, right here and now?'

Jibril tried to twist away and Macy snatched at yo's bandolier belt and they both lost their footing and waltzed sideways into a bank of cut flowers. Flurries of petals settling around them as Macy pinned Jibril down and told yo at length and in great and passionate detail exactly what she thought of yo's stupid so-called art. The acolytes twittered and wrung their hands, torn between trying to rescue their leader and making a record of the performance. A small crowd gathered and a pair of peace officers appeared. They managed to separate Macy and Jibril, but Macy, recklessly elevated by her anger, broke free and flew three metres in one bound and managed to land a solid punch on the side of the cosmo angel's face. She felt Jibril's teeth click under her knuckles and the cosmo angel went backward and sat down, shockingly red blood spilling from yo's pale lips, and then the peace officers got hold of Macy and hauled her away.

The drone captured everything. The footage was on the net inside an hour, and shot straight to the top of the charts.

Macy stood before the citizens' court the same day. Jibril, yo's cheek swollen and bruised, pressed charges; Macy refused to apologise or show remorse and wouldn't let Ivo Teagarden make an apology on her behalf. In the gallery, a little group of refuseniks began to boo and heckle and a majority of the audience shouted them down. The senior of the two peace officers who had arrested Macy asked for a vote, the audience overwhelmingly found Macy guilty, and the peace officer made a short speech about the necessity for everyone, born citizens and incomers alike, to respect the civic codes that enabled people to go about their business without fear or hindrance and told Macy that she would serve forty days'

community service, and the sentence would start immediately.

4.

Global warming and the release of vast quantities of methane and the subsequent catastrophic destruction of a substantial portion of the biosphere during the Overturn had caused massive perturbations in the heat engines that drove Earth's weather systems. Radical measures, such as the cloud of sunshade mirrors that cut the amount of sunlight falling on the Earth's surface, and the forests of synthetic Lackner trees whose sails removed vast tonnages of carbon dioxide from the atmosphere, had significantly lowered Earth's average global temperature, but it would be many decades yet before the planet's climate returned to something approximating pre-industrial conditions. In Antarctica, glaciers around the coast had retreated, ice-sheet extension in winter was much reduced, and during the brief summer ice and snow were entirely absent along most of the coast of the Antarctic Peninsula.

Sri Hong-Owen had built her home and a research complex on the coast of Graham Land, at the northern end of the peninsula. Her retreat, her fastness, her fortress of solitude, set above a fjord whose crooked mouth sheltered it from the cold currents, icebergs and fierce, salt-laden gales of the Weddell Sea. Sri had constructed a biome along the shore of the fjord, modelled on the ecosystem that had briefly flourished there during the warmest part of the Pliocene. Hummocky sedges thickened amongst the rocks of the tideline, and a heath vegetation of low, close-knit swales of Antarctic beech, Nothofagus antarctica, and dwarf willow, blueberry, Labrador tea and birch, grew up the steep sides, interrupted by small, lush meadows of grass and mosses that in the brief summer were bright with yellow buttercups and dandelions, bluebells, white asters, and pink and rust-red willowherbs. Hares and two species of vole grazed the heaths. Rookeries of Chinstrap and Gentoo penguins contested for space along the shore. There was a small colony of Weddell seals. Skuas and fish eagles rode the fierce, frigid winds. There was even a small wood in a sheltered valley beneath Sri's house, where Antarctic beech trees grew six or seven metres high amongst mossy rocks. Sri was walking there with the younger of her two sons, Berry, when her secretary called and told her about the problem on the Moon.

It was early March. Autumn. The beeches were draped in oranges and yellows. A scant snow fell from the grey sky, dry cold pellets pattering on moss and drifts of fallen leaves. Black squirrels made frantic guerrilla sorties to collect beech mast; they would soon go into hibernation and doze away the six months of darkness and sub-zero temperatures. Sri reprimanded Berry when he threw a stone at an unwary squirrel that came too close. He was a sturdy boy, shorter and heavier than his brother. Like Sri, he was wrapped in a quilted coat and quilted trousers, the coat's hood cinched tightly around his face as he kicked with aimless ferocity at the crumbling, moss-bearded trunk of a tree that years ago had fallen in one of the winter storms.

Sri had spent a lot of time thinking about Berry's future recently, trying to find something he could be good at, something he could enjoy. He was a sulky, obdurate child, not especially bright, showing little interest in anything he couldn't eat or break, but there must be a spark somewhere inside him, something she could kindle.

Now, she made him kneel beside her and showed him the invertebrate life wriggling in the thin loam under the mossy log. Dozens of tiny springtails (the only terrestrial invertebrate in Antarctica, before the Overturn), worms recoiling into their burrows, pill bugs, a large black beetle with curved pinchers. There were more than two hundred species of insects in the wood and the heaths and meadows - even a species of bumblebee that Sri had introduced to pollinate the summer flowers. Berry was searching for another beetle, down on his hands and knees in the leaves and moss, explaining how he could stage a fight between different insects, something that reminded Sri of Euclides Peixoto, when her phone rang.

'There's a problem at Oxbow,' Yamil Cho said, without preamble. 'A code ten.'

Oxbow was the superbright facility. Code ten meant that there had been an attempted breakout, and fatalities.

'How bad?'

'Five down, plus collateral damage. Your attendance has been requested. I have taken the liberty of arranging transport - the Uakti.'

It was the shuttle that had been used as a test bed for the first of the new fusion motors. Yamil Cho told Sri that it could make the trip point-to-point in less than six hours.

Berry had been kicking at the dirt and stamping on insects he'd uncovered. Now he started to make excited noises, trying to get his mother's attention. She turned her back on him and said to her secretary, 'When is it due?'

'A little over an hour. A sub-orbital lob from Brasilia.'

'Come pick me up when it's here,' Sri said, and called to Berry.

He trotted over, proudly displaying the treasure he'd unearthed. The brown arc of a human rib-bone, no doubt from a casualty of one of the twenty-first-century wars fought over oil and methane clathrate fields in the Weddell Sea. When Sri had begun her work here, there had still been remnants of oil platforms out in the open water, and tankers and warships sunken or grounded along the coast. She'd pulled in every favour to have them broken up and removed, and had done much else to clean up the peninsula. Removing crashed planes and the carcasses of tanks and other vehicles. Uplifting a barracks and a graveyard. Using bacteria she'd cut herself to digest a vast sluggish spill of oil that had accumulated in a deep trench thirty kilometres offshore, the source of hard tarry cakes that had washed up along the shore after storms. But there'd been a lot of fighting here, and things had lasted a long time in the cold. It was still possible to turn up souvenirs of the wars almost anywhere along the peninsula. Weapons and ammunition, clothing, trash, and bones like the rib Berry clutched like a frail dagger.

Sri felt a shiver of presentiment and told her son to throw the grim little memento away, speaking so sharply that he did what he was told without arguing.

'There's more, under the log,' he said.

'Someone will come and clean it up,' Sri said. 'You run to the house and get some hot chocolate from the housekeeper.'

'I didn't do anything wrong.'

Berry's face was set in a scowl that Sri knew could quickly turn to tears and a tantrum. She dropped to one knee and cuddled him and said, 'I know you didn't. But I have to go away for a few days, and I need you to be my good little soldier while I'm gone.'

'Are you going back to Brasilia? Can't I come this time?'

'I'm going to the Moon, and much as I'd like you to come with me I'm afraid you can't. Don't pull a face. I'm not taking Alder either. Go on home now, quick as you can!'

As her son scampered away towards the house, Sri set off in the opposite direction. She needed a little time alone. She wanted to think about the implications of the breakout and the peremptory summons, work out her best response.

She climbed out of the wood, following a path that switchbacked up the side of the valley to a crest of sedgy heath. Tramped along the ridge as it rose eastwards, climbing through fields of lichen-blotched boulders, at last reaching a wide shelf of bare rock that gave her a panoramic view down the crooked arm of the fjord to the open sea. Facing into the cold, clean wind and thin flurries of snow, she could survey the entirety of her little kingdom. The steep patchwork heath cut by the neat fold of the little wooded valley. The glass-and-steel boxes of her house cantilevered above the western side of the valley, and the little campus of the research complex spread along the shore towards a prospect of snow-capped mountains. The dark water of the fjord was littered with bergy bits. Beyond its narrow mouth, fleets of icebergs sailed the wide sea, and three vertical lines scratched the grey sky at the horizon, precise as brushstrokes in a Japanese print, feathering into tiny plumes that bent northwards: smoke lofted by volcanoes that had become active after the lithostatic pressure of the Antarctic ice cap had diminished.

But the ice was returning. Winter came a little earlier every year to the fjord, left a little later. In fifty years or so its grip would be permanent. Everything Sri had quickened here, the little wood, the heaths and meadows, the scampering squirrels and the hares and voles: all of it would soon be gone, yielding to snow and ice.

A fine lesson in impermanence, Sri thought. Nothing remained the same for ever. Every niche-clinging individual or species that stubbornly refused change invited extinction. Adaptability was the key to survival. The world was being revived, not remade or restored, and change was the engine of revival. Oscar Finnegan Ramos and the other green saints promoted a holy mission of returning the planet to a prelapsarian paradise, but with the exception of a few garden spots protected by vast expenditures of energy and effort it would not be possible to reverse entropy and replicate and maintain a historical state. Their vision was a mirage. The world must be free to find its own point of equilibrium. Reclamation and remediation were a beginning, not a means to an end. After the world was reclaimed and renewed, human beings must relinquish control, allow new states to emerge.

Sri believed that the biosphere was a vast space of possibilities. Billions of years of life on Earth had explored only a small part of that space. So much more could be unlocked with just a small toolkit and a little imagination, and nothing was unnatural because nature was not limited to the variations on a few themes that evolution had so far realised. She dreamed of a thousand Earths, all different. A thousand gardens of plenty, harmonious, burgeoning with wonders.

She knew that it would take her many more years than the century and a half granted her to realise those dreams, and knew that at least one other person not only shared her ambition but could give her the key to true longevity. Until now, she had served Oscar Finnegan Ramos dutifully. He had set her on the career that had consumed her life. He had underwritten her research and protected her from the scorn and political manoeuvring of her rivals, and the fanatics who believed that change was dangerous and stasis holy. But all the while, Avernus - or rather, the ideal that Sri had erected in her mind's eye - had been her secret mistress. Sri had begun to grow away from Oscar Finnegan Ramos's ideas long before she had travelled out to Callisto and Europa; the superbright facility on the Moon was part of her increasing independence. It had provided a number of wonders, including the improved fusion motor, but containment had always been a major problem. Keeping the truth from Oscar; keeping the superbrights safely penned.

And now containment had been breached again. Security precluded transmission of any details. Beyond the plain fact that five superbrights had died, Sri wouldn't know how bad the incident had been until she had talked with the staff and seen the damage for herself. But she was certain that things had reached a critical point this time. She'd just returned from a punishing month in Brasilia. Committees, policy reviews, think tanks, long-range planning sessions with the Joint Chiefs of Staff. The enemies of reconciliation were in the ascendant, emboldened by the death of Maximilian Peixoto and the failure of the biome project. A senior senator who had championed trade with the Outers had been unseated by a sex scandal. An emergency bill authorising funding for the conversion of several freighters into warships had been rushed through. Everyone gossiped about power shifts within the legislature and amongst the families. There were rumours that the Pacific Community was about to embark on its own programme of shipbuilding.

Rothco Yang, the representative from Rainbow Bridge, was deeply pessimistic. 'We are talking about conciliation instead of reconciliation now,'

he told Sri over dinner. 'Appeasement. Minimising the political and economic damage in the event of war between Earth and the Outer System. Rainbow Bridge has never wanted war. We have always championed the mutual benefits of peace and cooperation, but that is becoming increasingly difficult.'

Peace was still and would always be the best option, but support for peace was dwindling on both sides. Rothco Yang said that none of the Outer cities, not even Rainbow Bridge, could accept the terms that the most radical of Earth's radical greens were demanding - complete surrender of political and economic autonomy, and an end to so-called anti-evolutionary genetic engineering and exploration of the outermost reaches of the Solar System.

'Many in your government are in no mood to make concessions, or recognise our isolationist position,' he said. 'And at the same time, several cities in the Saturn System are eager for confrontation. They believe that the long supply line between Earth and Saturn will fatally weaken any hostile forces. Yet they are even more vulnerable. Their cities and settlements are fragile bubbles of air in an unforgivingly hostile environment. It would take very little to bring them down.'

Rothco Yang looked exhausted. His jaunty optimism was entirely gone. It was almost possible to believe the face-saving fiction that he must soon return to Rainbow Bridge because his health was badly compromised by Earth's gravity and raw unaltered air. He and Sri parted on equable terms, wishing each other the best, promising to stay in touch, but they both knew that they were laying to rest a worthy but lost cause.

No, it was no longer the season for peace and reconciliation. Sri remembered another conversation in Brasilia, much shorter, far more unpleasant. She'd been lunching with her aides and two fellow scientists during a break in a long and hostile session of a subcommittee on protocols and ethics of research into the human genome, and Euclides Peixoto had come over to their table. The smiler with the hidden knife. After a brief exchange about the aftermath of the biome project, he'd asked Sri what great project she would turn to next.

'That's not my decision. As always, I'm at the service of your family.'

'Really? I know you've been happy to serve because our interests have always coincided with yours. But I wonder what you'll do now things are changing,' Euclides Peixoto had said, adding that from now on he'd be following her career with great interest.

Sri wished that all her enemies could be so lazy and foolish. So obvious. And although Euclides's crude threat had been unsettling, it was also a useful reminder that she must soon make a choice. Now, on the ridge above her fortress of solitude, under a grey and louring sky with Antarctic wind flensing her to the bone, she realised that she'd already chosen. She could have refused the summons to the Moon, and it was likely that Oscar could have protected her from the consequences, but although she could not be entirely sure that she'd survive it she was glad that she was going. For a little while, she could feel unburdened. She had thrown off the past and could face the future's garden of forking paths if not with hope then at least with equanimity.

At last her attention was caught by a bright scratch far across the ocean, moving fast, coming out of the north and making a sharp turn towards the shore, its thunder catching up with it now, rolling across the bleak hilltop where Sri stood. She watched as the sleek little shuttle slipped in above the fjord, slightly lower than where she stood, its twin ramjets rumbling in turbofan mode. It was painted black above white like the killer whales she'd reintroduced to the Antarctic biome. Red lights flashed at the tips of its stubby wings. Its tail fin was decorated with the green flag of Greater Brazil. As it eased towards the landing pad beyond the research complex, Sri called her secretary and told him to come and get her. A few minutes later, a small helicopter whirred up from behind the distant house.

The Uakti climbed in a steep curve above the Weddell Sea. Eighty kilometres up, at the edge of space, its fusion motor ignited and Sri, Yamil Cho, and the shuttle pilot were slammed back into their crash couches as it accelerated towards escape velocity.