'He did very well. I'm proud of him.' Sri told the old man how Alder had seduced the young scientists and found out about Avernus's secret garden. 'I would have made contact with her if it hadn't been for the incident at the opening ceremony. If I hadn't been recalled from Europa. I was this close,' she said, holding her thumb and forefinger about a centimetre apart.

'I read the report you made to the Senate Subcommittee for Extraterrestrial Affairs. But I would very much like to hear the story in your own words. Tell me everything, and don't hold back.'

Sri talked for an hour. She gave a thorough account of the crude attempt to sabotage the construction project, the murders of Ursula Freye and Speller Twain, and the involvement of the diplomat Loc Ifrahim, and gave her reasons for believing that Euclides Peixoto could have gone over to the pro-war faction of the family. She described Avernus's hidden garden and the little habitats that Alder had seen scattered across the cratered face of Callisto, talked about the potential of the weed farms in the Europan ocean, and said that in her opinion the split between the older and younger generations of Outers was irreconcilable.

'I think it was a mistake to try to help the older and more conservative Outers to keep control,' she said. 'We should instead be making overtures to the rising generation. I glimpsed a few of their secrets. I think there's much more to be uncovered, a wealth of opportunity. But we must move swiftly, because they are definitely on the brink of a rapid and unpredictable phase of expansion. In only a few years, there will be dozens of new communities at the edge of the Solar System, each one evolving in a different direction. So we must forge a lasting relationship now, and make ourselves allies of the diaspora. It's our only chance to exert any influence over it.'

Oscar thought about this. Sri, used to his silences, sipped tea grown cool and bitter and watched the sea wind flatten grasses along the crests of the dunes, move through the boughs of the pines.

At last, the green saint said, 'You're the cleverest of my proteges. It doesn't do any harm telling you that because you already know. But I think you are also the most romantic. It's not a criticism. It's an essential part of your creative imagination. You wouldn't have come so far without it, or done such great things. But it can be a weakness, if you are not careful.'

'You think I've been seduced by the mystery and exoticism of the frontier? Everything I've told you is entirely factual. I thought long and hard about it on the voyage home and it all points to one conclusion. That we have a small and narrowing window of opportunity. That if we don't make an alliance with the Outers now, it will soon be impossible. Our only alternative will be to take control by main force.'

'I think you need to take some time to fully absorb the meaning of your experiences. To think carefully and deeply about the implications of everything you learned. You need some grounding. You need to develop a little perspective,' Oscar said.

He was sitting cross-legged, the soles of his feet tucked in the angles of his knees. An ancient and potent homunculus, not quite human, his joints swollen under dark leathery skin, his head seeming too large for his slight, crooked body, his ears pendulous, his naked wrinkled scalp blotched with colonies of benign cancers. Sri's guru, her master. His body was studded with medichines that filtered his blood, manufactured powerful antibodies against any trace of infection, destroyed cancerous cells, and continuously updated a medical team in Carrizalito. He was plugged into feeds from satellites and weather stations, and the consensus worked up from data collected by thousands of tiny free-floating machines that monitored the sea. He had direct access to the president of Brazil and to leaders and green saints in every country on Earth. On a whim, he could call up a fleet of construction robots and plant a forest, or have a mountain reshaped into his own likeness. A permanent garrison of soldiers protected a wide perimeter around his hermitage, wolves patrolled the dunes, and he had direct control of a statite hung in stationary orbit two hundred kilometres above, capable of zapping anyone or anything inside the security perimeter with its X-ray laser.

Now, as Oscar studied her with a sad and troubled gaze, Sri felt a falling sensation. Felt the first real taste of failure. The collapse of the biome partnership hadn't much troubled her: at bottom, it had never been anything more than a political gesture, and it had usefully made plain the divisions among the Callistans and within the Peixoto family. And although she had been angry and humiliated because she had been recalled before she could make contact with Avernus, she was over that now, had renewed her determination to prove herself a match for the woman's powers, or even surpass her. But if she couldn't convince Oscar that the family must redouble its efforts to forge a peaceful partnership with the Outers, if she could not persuade him about the vast and untapped potential of their rising generation, she would have to renounce her guru and give herself to the cause of Arvam Peixoto and the other enemies of reconciliation. She would have to give herself to war. She wondered, as she bore Oscar's gaze, if he knew this; if he knew about the footage she'd sent to Arvam, and all the rest.

'Come with me,' he said at last. 'I want to show you something.'

They walked through a flower garden decorated with wrack from villages and towns drowned by the rising sea level and cast up along the beach - calcined bottles and crockery, ancient tin signs, plastic bottles of every shape and size scoured white by years of immersion, pieces of driftwood rubbed into shapes smooth as muscle. Beyond this, in the pale dry sand at the top of the beach, was a pen fenced with wire mesh nailed to stakes. The green saint climbed nimbly over the mesh and knelt down and carefully scooped a narrow trench in the sand, exposing a few soft white spheres. Turtle eggs.

'I tried this last year,' Oscar said. 'The fence keeps lizards and crabs from eating the eggs - you have to secure it deep in the sand. When the eggs begin to hatch, I'll pull it up and let the hatchlings scamper down into the surf.'

'Did any of last year's batch come back?'

'Not that I know of.'

'I suppose the sea isn't ready for them.'

'A few might be out there. It is possible that they went back to some other beach. But you're probably right. There's still so much to make good. These might not come back either,' Oscar said, as he pushed the sand back over the eggs. 'But we have to keep trying.'

Sri said, 'If this is some kind of parable, I'm not sure if I completely understand it.'

Oscar stood up, brushing sand from his knees. 'We are engaged with a great work of penance. It's hard work, and perhaps much of what we plan to do is impossible. We'll always fail at it. But we have to try, because it is what we do. Making amends - it is why we are here. Reconciliation with the Outers is part of that. It is not a thing in itself. It is not for anyone's benefit or profit.'

'There's more that we can do. Much more. I'll go again. As soon as you like.'

'I want to build a peaceful link with the Outers as much as you do, but it has to be on their terms. If they refuse our efforts, so be it. Do you understand, my dear?'

'Of course.'

What else could she say? Oscar Finnegan Ramos was powerful and capricious and not quite human. He could take away her laboratory, her career. He could order the satellite to kill her as she walked back to where Yamil Cho waited by the car. An incandescent bolt flung from orbit would vaporise her, leave nothing but a vitreous crater smoking in the dunes.

'There have always been members of the family who have been against reconciliation,' Oscar said. 'And they have been speaking more loudly now that the biome project ended so suddenly and unsuccessfully. We will not encourage them with another failure, or the possibility of failure. So we will retrench. We keep channels open, we wait until the right moment, and then we try again.'

The green saint was two hundred years old. He had long ago learned patience, how to take the long view. But Sri believed that this time he was wrong. She knew that things were changing with tremendous speed. There was not enough time to wait until the small scandal of the biome project died away, not enough time to prepare the ground for another approach. On the trip back to La Paz, the flight to Antarctica, and for many days afterward, she thought long and hard about what she should do next. About peace, and war.

PART TWO.

1.

One day, just before the boys were due to board the shuttle that would take them into orbit for one of their regular sessions of zero-gravity combat practice, Father Solomon told them to put on their pressure suits. 'Today you will attempt something new.'

Carrying their globular helmets in the crooks of their arms, the boys followed Father Solomon and the other three lectors into the shuttle's padded cargo bay and sat in obedient silence for two hours, strapped into bench seats, as the shuttle flew in a low, sub-orbital lob halfway around the Moon. After it landed, the boys fastened their helmets over their heads and each checked his neighbour's lifepack. They were clumsy in their stiff pressure suits, bumping into each other in the crowded space, excited and apprehensive. The air in the cargo bay was pumped out, a ramp dropped, and the lectors herded the boys in single file down its short slope onto the surface.

Dave #8 was one of the last to leave, following the others out of the shadow of the shuttle. A few of the boys fell to their knees, arms wrapped around their big round helmets. The rest, like Dave #8, stood and stared rapt with wonder at a desolate plain stretching away towards a range of hills, softly rounded as pillows, that curved from horizon to horizon. Everything was in clear and distinct focus, and because the plain was spattered with craters and tailings of rock of every size, and the hills were sharply silhouetted against a blackness as absolute as the end of the world, it was hard to shake off the impression that this was the floor of a room lit by a solitary light glaring low under a sooty ceiling. A light stronger than any Dave #8 had ever seen before, too bright to look at even through the polarised faceplate. It was the sun, a brilliant white spotlight swimming in a vast and absolute blackness, its harsh light reflected by the naked landscape all around . . .

Someone shouted wildly and three boys bounded away, chasing each other across the bright ground. Father Solomon and Father Ramez went after them, calling to them, ordering them to stop, to come back; Father Aldos and Father Clarke moved amongst the rest of the boys, gently encouraging those who had fallen to their knees to get to their feet, telling the others to line up.

Dave #8 took his place in the two ranks that he and his brothers formed by unthinking habit. The three boys who had run off were led back and joined the others without being admonished, and Father Solomon told them that they would pair up and each pair would be given a different set of coordinates. They would hike out to a selected spot, find a flag dropped there by a drone, and bring it back. It was a simple training exercise, the first of many that would familiarise them with every kind of landscape on the lunar surface. Father Solomon said that he knew that they would find this strange and intimidating at first, but he also knew that they would do well, and would not disgrace themselves or fail to complete their task.

Dave #8 was paired with Dave #14, and they set off towards a point northwest of the shuttle and three kilometres away, bounding along in the steady, stiff-kneed lope they'd long ago mastered in exercises in the gymnasium. The floor out here - the surface - was covered everywhere with a velvety powder that looked as if it would blow away on the slightest breath but gave only a little under Dave #8's boots. Sprays of dust feathered away from his boots with each footfall and dust clung to his overshoes, staining their white weave with smudges of charcoal black. His boots and the boots of his brother printed sharp impressions in the dusty surface; when he paused and looked back at the way they had come, he saw an intertwined double track of prints that shone glassily in the relentless glare, receding away towards the shuttle. Its boxy shape, squatting on splayed and skeletal legs, looked strange and small and lonely and fragile in the empty moonscape under the black sky and the dazzling glare of the sun, and Dave #8 felt a sudden dizziness as his sense of perspective swoopingly enlarged and he realised that some of the features of the moonscape that looked small and close were really large and far away. It was difficult to estimate distances because in the vacuum everything far was as sharply focused as everything close at hand, and there was nothing to give any sense of scale. But those softly rounded hills must be big and far away, Dave #8 thought, because they looked no closer nor any larger than before, yet according to the navigation display glowing in the lower right-hand corner of his faceplate he and Dave #14 had already slogged across a kilometre of open ground towards them . . .

Dave #14 told him to keep moving and he hurried to catch up. His breathing was harsh and intimate inside his helmet and his heart was beating quickly and strongly. He was noticing everything around him and everything was new and exciting and charged with significance and the high resolution of reality. The sun was at their backs and threw their shadows ahead of them, flickering across low undulations in the surface as they bounced along, and the surface was a warm golden-brown straight ahead but looked darker to either side and grey or black directly underfoot. It was littered with little rocks sunk to different levels in the dust, and every rock cast a sharp shadow and was peppered and pitted with tiny holes. Craters from micrometeorite impacts, Dave #8 thought, and the connection between what he had learned and what he saw struck a bright snap of pleasure.

The plain all around them was cratered too, craters of every size from pinholes to small cups of smashed rock to deep bowls that could have swallowed the shuttle whole. The interior slopes of some of the craters were themselves pockmarked with smaller craters, and the larger craters had aprons of ejecta extending beyond them, rocks excavated and flung out by the impacts that had punched holes into the surface. Some of the rocks were huge: Dave #8 tracked two of his brothers bounding past a distant clump of fractured blocks bigger than the shuttle, then realised that he had fallen behind Dave #14 again.

The red dot that marked Dave #8's position on his navigation display crept towards the yellow cross of the designated coordinates, until at last he and Dave #14 reached the edge of a crater at least a hundred metres across. Its rim was dazzling white and slightly raised, and its dished interior sloped steeply down to a flat floor covered everywhere with clumps and carpets of broken rock.

Dave #8 looked all around and said, 'I can't see the stars. I suppose the glare of the sun hides them. But where is Earth? Surely it shines much more brightly than the stars? Do you think we are on the far side, the side that faces away from Earth?'

'You have too much imagination. It makes you think too much about things that aren't important,' Dave #14 said.

He was a stolid fellow, practical and dogged and tireless. As Dave #27 once put it, he would bash away at an intractable problem until he cracked it open by sheer force of will.

'The only thing we have to think about right now is retrieving the flag,'

he said. 'And if you had been studying the floor rather than the sky you would have already spotted it.'

Dave #8 looked at where Dave #14 was pointing and saw a red triangle standing in front of a squarish block of rock at the far side of the crater's floor. He said doubtfully, 'Is it safe to climb down?'

'We have been told to bring the flag back with us, so we will have to go down there,' Dave #14 said.

They descended a shallow slope that quickly grew steeper, so that they had to crab down in a fast-settling welter of dust, dust clinging to the legs and arms and chest-plates of their pressure suits, settling on their visors and leaving smears when they tried to wipe it off. Dave #8 kicked a fist-sized rock that rolled down the slope ahead of him, slowly gathering speed as it tumbled until it silently smashed into a large half-buried block and lay still. Dave #8 felt a brief stab of fear. His suit was a fragile bubble of air and warmth; one misstep could send him cartwheeling, shatter his faceplate against some hard and unforgiving edge.

Dave #14 trotted out across a bank of small debris and gripped the wire shaft of the flag in both gloved hands and plucked its arrowhead-shaped root from the ground. Its red triangle shone with hallucinatory brightness against the monochrome rocks scattered all around. When Dave #8 reached his brother, he realised that the shuttle was no longer visible. That the two of them were more alone than ever before in their lives. Only the slanting sides of the crater circled around them; only the black sky and the pitiless spotlight of the sun above.

'One of us should have stayed at the top in case the other got into trouble,' he said.

'We'll do that next time,' Dave #14 said. 'Now, I want to be the first to get back.'

They followed the trail of their bootprints across the soft contours of the moonscape towards the shuttle, but the way back was not like the way forward. The short walk had changed them forever.

There were many more exercises on the surface. Long hikes across every kind of terrain. Navigating from point to point. Searching out caches of supplies. Teams set against each other, armed with pistols that fired pellets of compressed red powder that splashed against unlucky or less skilful targets and marked them as casualties in war games. The exercises were always held on the Moon's far side, never under a sky that held the blue-and-white crescent of Earth.

Some sixty days after the first excursion, Dave #8 was tramping alone through a saddle-shaped valley between two rounded peaks of the Montes Cordillera, pulling a small sledge of supplies, when he came across a trail of bootprints. They were a little larger than his own boots, so they had not been made by one of his brothers, and the pattern of the cleats was different. They could have been made yesterday or a hundred years ago; in the lunar vacuum, bootprints lasted for millions of years, until at last they were erased by the slow but relentless degradation of micrometeorite impact. He followed the trail as it swung around a shallow crater, down a slope to where it ended in a mazy jumble around parallel wheel-tracks left by some kind of small vehicle that had turned here and headed east, in the direction from which it had come.

Dave #8 stood still, struck by the thought that he could follow the tracks eastward past the great ring of the Montes Cordillera and on, through the knobby hills and peaks of the Montes Rook Formation, to the Orientale basin at the very edge of the Moon's nearside. And see at last Earth hanging blue and white and lovely in the black sky. He was in the middle of a hike that was scheduled to last forty-eight hours. By the time the lectors realised that he was missing, he would be unbeatable. For a moment the thought was as strong as a muscle clenching, but then it faded. What would he do when he reached the nearside? Where would he go? How would he live?

Dave #14 had been wrong, he reflected, as he tramped back to his sledge. He didn't have too much imagination; he had too little.

2.

Now that the J-2 test programme was up and running, the pilots were rotated back to Earth on a regular basis for personal leave, morale-boosting visits to the plant where their birds were being assembled, consultation sessions with the designers of the new carrier ship, the Glory of Gaia, and meet-and-greet promotional junkets amongst higher echelons of the armed forces and the interlocked worlds of politics and the arms industries. Luiz Schwarez returned from one of the latter with news that more pilots were going to be cut to fly the J-2, and some of them would be from the European Union.

'It makes all sorts of political sense,' he told Cash Baker and Colly Blanco a couple of days later. 'The Europeans stood by us when it looked like we might have to go to war against the Pacific Community, we have deep and long-standing economic ties with them, and they like the Outers even less than we do. After all, they refused to participate in any of the nonsense about peace and reconciliation, despite strong incentives to do so. If we go to war against the Outers-'

'When we go to war,' Cash said.

'When we go to war, then, we will greatly benefit from their help,' Luiz said. 'The Europeans are the oldest and richest power bloc. There's talk that they will help underwrite the costs of building the Glory of Gaia and the other long-range ships. In exchange, they get access to our technology the new fusion motor, and the hyper-reflexive upgrades.'

'As long as the brass remembers that we're the first and best when it comes to taking the fight to the Outers, I don't mind who comes along for the ride,' Colly Blanco said.

'I hear that,' Cash said.

'You and me, we'll kick their asses,' Colly said.

He was the youngest pilot in the J-2 programme, just turned twenty-one, and a much better pilot than Cash had been at that age, although not as good as Cash was now, not quite. A fierce, fearless little tyke from a mining town in the foothills of the Andes, who claimed that he'd learned to ride a horse and rope a bull before he could walk, fly before he could read. He was leading the other two through the dark corridors and rooms of the old city's service levels: they were hunting rats, a favourite activity of the pilots when they were off-duty and confined to base. They wore night-vision goggles equipped with motion detectors, carried little pistols that shot taser darts.

At an intersection where two corridors crossed each other at oblique angles, Colly held up a hand, then pointed left. Thirty metres away, a fuzzy blotch pulsated like a slow and steady heart in the dim shadows. Twenty rats, easily. Maybe even thirty. Cash and Luiz flattened against the wall behind Colly, jumped out into the intersection when he did. The blotch split into a whirling flurry as rats scurried away in every direction. Cash picked a target and shot, saw bright sparks flare down the narrow perspective of the dark corridor as taser darts struck the floor and the walls.

A brief search turned up only one corpse. A lean brindled grandfather rat more than half a metre from its nose to the tip of its tail, fitted inside a hollow ball that had been shaped from a chunk of foamed wall insulation by careful nibbling. It had elaborate notchings in its ears that Luiz claimed were tribal or status markings. A piece of well-chewed plastic was slung around its neck by a loop of wire.

Cash and Luiz didn't argue when Colly said that it was his kill.

'Little fuckers're getting smarter,' Colly said, and booted the dead rat inside its ball of foam-armour into the shadows at the far end of the corridor.

'They're learning,' Luiz said. 'Developing culture. One of the medics reckons those notches are some kind of graphic alphabet. She's trying to decode it.'

'Is that the woman who's giving you some?' Cash said.

'A gentleman never tells,' Luiz said. He was as dapper as ever, a red silk scarf knotted at the throat of his coveralls, black hair sleeked back from his narrow brown face.

They weren't bothering to keep quiet now. They knew that all around them rats were crouching watchfully in cavities inside walls, in ducts and cableways. That news of their presence was spreading on the rat bush telegraph. Still, they weren't quite ready to give up the hunt and return topside.

The corridor they were following made a bend through ninety degrees. A faint blue light flickered through an open doorway ahead. They crept towards it one after the other. Luiz held up his hand, counted down from three by folding his fingers and thumb. They swung into the doorway, pistols locked on the source of the light, an ancient photoframe which someone had left on a desk a century ago. It was playing a short clip of a man swinging a small child around and around on a beach. White sand and hot sunshine and the vivid blue ocean of a summer's day of the long ago, little sailboats out on the water. The old part of the base was full of mementos of abandoned lives like this. Clothes on hangars inside closets. Freezers stuffed with mummified food. A children's playground littered with toys.

Luiz picked up the photoframe, briefly studied it, then tossed it to Cash, saying, 'Think they're still alive, on some moon or other?'

'The kid, you mean?'

'Maybe the man too. Some of those Outers live a long time. A lot more than a hundred-odd years.'

'You know what you should be asking?' Colly said. 'You should be asking what switched that thing on.'

Luiz and Cash stared at him, and there was a sudden scratching and skittering overhead and ceiling tiles gave way and a blizzard of dried rat shit poured down. Colly swore vividly and fired his taser at the holes in the suspended ceiling, bolt after bolt lighting up the room with hot white sparks and sending shadows dancing wildly. Cash watched the shadows over the sight of his taser, looking for movement and finding none. Luiz was laughing.

'What's so fucking funny?' Colly said.

'They ambushed us,' Luiz said, and started laughing again.

'It could be worse - they could have used rocks instead of turds,'

Cash said, barely getting the words out before he too was convulsed with laughter.

Colly glared at them in disgust, brushing commas of rat shit from his coveralls with abrupt motions, running his fingers through his cropped hair and violently shaking his head.

'These rats, they're getting very smart indeed,' Luiz said, as they walked back down the dark corridor. 'They set a trap, so they must be able to think ahead. To plan. And they worked out what would lure us into their trap, so they must be able to think like us, too.'

Colly shook his head. 'Smart rats, man. Who needs smart rats?'

'Sri Hong-Owen. The ancestors of those rats suffered so that we would not the in vain,' Luiz said.

'Don't riddle me, stringbean.'

'He means Sri Hong-Owen tested her stuff on the rats before she did us,' Cash told Colly.

'So you might say that, in a way, the rats are our brothers,' Luiz said.

'Your brothers, maybe,' Colly said, with the hard look he used when he believed that he was somehow being insulted or set up as the fall guy in a joke.