"Yes," Titus said, with a long-suffering sigh, "and visit parts of the ship you're expressly not allowed to go to. That, I'm afraid, can't go unpunished." He softened his voice now, as he always did when he was about to discuss something of genuine importance. "This ship is our home-our only real home-and we have to feel like we live here. That means feeling safe in the places where it's right to do so-and knowing where it isn't safe to go. Not because there are monsters or anything silly like that, but because there are dangers-adult dangers.

Machinery and power systems. Robots and drop shafts. Believe me, I've seen what happens when people go into places they're not meant to go, and it usually isn't very pleasant."

Sky did not doubt his father for an instant. As head of security aboard a ship which generally enjoyed political and social harmony, Titus Haussmann's duties usually concerned accidents and the very occasional suicide. And although Titus had always spared Sky the more intimate details of how it was possible to die aboard a ship like the Santiago, Sky's imagination had done all the rest.

"I'm sorry," Constanza said.

"Yes-I'm sure you are, but that doesn't change the fact that you took my son into forbidden territory. I'll be speaking to your parents, Constanza, and I don't think they'll be best pleased.

Now run along home, and perhaps in a week or two we'll review the situation. Very well?"

She nodded, said nothing, and left along one of the curving corridors which radiated away from the intersection where Titus had cornered them. It was not really far to her parents'

domicile-no part of the Santiago's major habitation section was far from any other part-but the ship's designers had cunningly avoided making any route too direct, except for the emergency crawlways and the train lines which reached down the spine. The snaking general-use corridors gave the illusion that the ship was considerably larger than its true size, and two families could live almost next to each other and feel that they lived in entirely different districts. Titus escorted his son back to their dwelling. Sky was sorry that his mother was outside, for-despite what Titus had said-her punishments were generally a shade more lenient than those his father prescribed. He dared to hope that she was already back aboard ship, having returned from her shift early, the work on the hull completed ahead of schedule, and that she would be waiting for them when they reached the nursery. But there was no sign of her.

"In," Titus said. "Clown will take care of you. I'll be back to let you out in two, possibly three hours."

"I don't want to go in."

"No-and if you did, it wouldn't be much of a punishment, would it?"

The nursery door opened. Titus propelled his son into the room without stepping across the threshold himself.

"Hello, Sky," said Clown, who was waiting for him.

There were many toys in the nursery, and some of them were capable of holding limited conversations-even, fleetingly, giving the impression of true intelligence. Sky sensed that these toys were built for children of about his age, designed to mesh with a typical three-year-old's view of the world. In most cases, he had begun to find them simplistic and stupid not long after his second birthday. But Clown was different; not really a toy at all, although not quite a person either. Clown had been with Sky for as long as he remembered, confined to the nursery, but not always present even then. Clown could not touch things, or allow himself to be touched by Sky, and when Clown spoke, his voice did not come from quite the place where Clown stood-or seemed to be standing.

Which was not to say that Clown was a figment of his imagination; without influence. Clown saw everything that happened in the nursery and was punctilious in telling Sky's parents when he had done something that required reprimanding. It was Clown who told his parents he had broken the rocking horse, that it had not been-as he had tried to make them think-the fault of one of the other smart toys. He had hated Clown for that betrayal, but not for long. Even Sky had understood that Clown was, apart from Constanza, the only real friend he had, and that there were some things Clown knew that were beyond even Constanza.

"Hello," Sky said, mournfully.

"You've been banished here, I see, for visiting the dolphins." Clown stood alone in the plain white room, the other toys concealed tidily away. "That wasn't the right thing to do, was it, Sky? I could have shown you dolphins."

"Not the same ones. Not real ones. And you've shown them to me before."

"Not like this. Watch!"

And suddenly the two of them were standing up in a boat, out at sea, under a blue sky. All around them the waves were broken by cresting dolphins, their backs like wet pebbles in the sunlight. The illusion of being at sea was marred only by the narrow black windows which ran along one side of the room.

In a story book, Sky had once found a picture of someone else like Clown, dressed in puffed-out, striped clothes with big white buttons, with a comical, permanently smiling face framed by bouffant orange hair under a soft, sagging striped hat. When he touched thepicture in the book, the clown moved and did the same kinds of tricks and vaguely amusing things that his own Clown did. Sky remembered, dimly, a time when his response to the Clown's tricks had been to laugh and clap, as if there were nothing more that could be asked of the universe than to provide the antics of a clown.

Now, subtly, even Clown had begun to bore him. He humoured Clown, but their relationship had undergone a profound sea-change which could never be entirely reversed. To Sky, Clown had become something to be understood; something to be dissected and parameterised. Clown, he now recognised, was something like the bubble-drawing the dolphin had made in the water: a projection carved from light rather than sound. They were not really in a boat, either. Under his feet, the room's floor felt as hard and flat as when his father had pushed him inside. Sky did not quite understand how the illusion was created, but it was perfectly realistic, the walls of the nursery nowhere to be seen.

"The dolphins in the tank-Sleek and the others-had machines in them," Sky said. He might as well learn something while he was prisoner. "Why?"

"To help them focus their sonar."

"No. I don't mean what were the machines for. I mean, who had the idea to put them there in the first place?"

"Ah. That would have been the Chimerics."

"Who were they? Did they come with us?"

"No, to answer your last question, though they very much wanted to." Clown's voice was slightly high-pitched and quavery-almost womanly-but never anything other than infinitely patient. "Remember, Sky, that when the Flotilla left Earth's system-left the orbit of Mercury, and flew into interstellar space-the Flotilla was leaving from a system that was still technically engaged in war. Oh, most of the hostilities had ceased by then, but the terms of ceasefire had still not been completely thrashed out, and everyone was still very much on a war footing; ready to return to the fray at a moment's notice. There were many factions who saw the closing stages of the war as their last chance to make a difference. Some of them, by this time, were little more than highly organised brigands. The Chimerics-or more precisely, the Chimeric faction that created the dolphins-were certainly one of those. The Chimerics in general had taken cyborgisation to new extremes, blending themselves and their animals with machines. This faction had pushed those limits even further, to the point where they were shunned even by the mainstream Chimerics."

Sky listened and followed what Clown was telling him. Clown's judgement of Sky's cognitive skills was adept enough to prevent a lapse into incomprehensibility, while at the same time forcing Sky to concentrate intently on his every word. Sky was aware that not all three-year-olds could have understood what Clown was saying, but that did not concern him in the least.

"And the dolphins?"

"Engineered by them. For what purpose, we can't begin to guess. Perhaps to serve as aquatic infantry, in some planned invasion of Earth's oceans. Or perhaps they were simply an experiment which was never completed, interrupted by the war's decline. Whatever the case, a family of dolphins was captured from the Chimerics by agents of the Confederacion Sudamericana."

That, Sky well knew, was the organisation that had spearheaded the construction of theFlotilla. The Confederacion had remained studiously neutral for most of the war, concentrating on ambitions beyond the narrow confines of the solar system. After garnering a handful of allies, they had built and launched humankind's first serious attempt at crossing interstellar space.

"We took the dolphins with us?"

"Yes, thinking they'd come in useful at Journey's End. But removing the augmentation that the Chimerics had added was a lot harder than it looked. In the end it was easier to leave it in place. Then when the next generation of dolphins was born, it was found that they couldn't communicate with the adults properly unless they had the augmentation as well. So we copied it and implanted it in the young."

"But they ended up psychotic."

Clown registered the tiniest flicker of surprise, his answer not immediately forthcoming.

Later Sky would learn that in those frozen moments Clown was seeking advice from one of his parents, or one of the other adults, about how best to respond.

"Yes . . ." Clown said finally. "But that wasn't necessarily our fault."

"What, not our fault to keep them down in the hold, with only a few cubic metres to swim around in?"

"Believe me, the conditions we keep them in now are vastly preferable to the Chimerics'

experimentation lab."

"But the dolphins can't be expected to remember that, can they?"

"They're happier, trust me."

"How can you know?"

"Because I'm Clown." The mask of his face, ever-smiling, pulled into a more agonised smile. "Clown always knows." Sky was about ask Clown exactly what he meant by that when there was a flash of light. It was very bright and sudden, but completely silent, and it had come from the window strip along one wall. When Sky blinked he could still see the after-image of the window: a hard-edged pink rectangle.

"What happened?" he asked, still blinking.

But there was something very wrong with Clown, and indeed, with the entire view. In the instant of the flash, Clown had become misshapen, stretched and malformed in all the wrong directions, painted across the walls, his expression frozen. The boat in which they had seemed to be standing curved away in sickeningly distorted perspective. It was as if the entire scene had been rendered in thick wet paint which someone had begun to stir with a stick.

Clown had never allowed that to happen before.

Worse still, the room's source of illumination-the glowing imagery on the walls-became dark, then black. There was no light save for the faintest milky glow from the high-set window. But even that faded after a while, leaving Sky alone in utter darkness.

"Clown?" Sky said, at first quietly, and then with more insistence. No answer came. Sky began to feel something odd and unwelcome. It came from deep within him; a welling-up of fear and anxiety that had everything to do with a typical three-year-old's response to the situation and nothing to do with the gloss of adulthood and precosity which normally distanced Sky from other children of his age. He was suddenly a small child, alone in the dark, not understanding what was happening.

He asked for Clown again, but there was desperation in his voice; a realisation that Clown would already have answered him if that were possible. No; Clown was gone; the bright nursery had become dark and-yes-cold, and he could hear nothing; not even the normal background noises of the Santiago.

Sky crawled until he met the wall, and then navigated around the room, trying to find the door. But when the door shut, it sealed itself invisibly flush, and now he could not locate even the hair-thin crack which would have betrayed its position. There was no interior handle or control, for-had he not been banished to the room-Clown would normally have opened the door at his request.

Sky groped for an appropriate response and found that, whether he liked it or not, one was happening to him anyway. He was starting to cry; something he could not remember having done since he was much younger.

He cried and cried and-however long that took-finally ran out of tears, his eyes feeling sore when he rubbed them.

He asked for Clown again, and then listened intently, and still there was nothing. He tried screaming, but that did no good either, and eventually his throat became too raw for him to continue.

He had probably been alone only for twenty minutes, but now that time stretched onwards to what was almost certainly an hour, and then perhaps two hours, and then tortured multiples of hours. Under any circumstances, that time would have seemed long, but not understanding his plight-wondering maybe if it were some deeper punishment his father had not told him about-it was almost an eternity. Then even the idea that Titus was inflicting this on him began to seem unlikely, and while his body shivered, his mind began to explore nastier avenues. He imagined that the nursery had somehow become detached from the rest of the ship, and that he was falling away through space, away from the Santiago -away from the Flotilla-and that by the time anyone knew, it would be far too late to do anything about it. Or perhaps monsters had invaded the ship from beyond the hull, silently exterminating all aboard it, and he was the only person left aboard that they had not yet found, even though it would only be a matter of time . . .

He heard a scratching from one side of the room.

It was, of course, the adults. They worked the door for some time before persuading it to open, and when it did, a crack of amber light spilled across the floor towards him. His father was the first to enter, accompanied by four or five other grown-ups Sky could not name.

They were tall, stooping shapes carrying torches. Their faces were ashen in the torch-light; grave as storybook kings. The air that came into the room was colder than it usually was-it made him shiver even more-and the adults' breath stabbed out in dragonlike exhalations.

"He's safe," his father said, to one of the other adults.

"Good, Titus," a man answered. "Let's get him somewhere secure, then we'll continue working our way downship." "Schuyler, come here." His father was kneeling down, his arms open. "Come here, my boy.

You're safe now. No need to worry. Been crying, haven't you?"

"Clown went away," Sky managed.

"Clown?" one of the others asked.

His father turned to the man. "The nursery's main educational program, that's all. It would have been one of the first non-essential processes to be terminated."

"Make Clown come back," Sky said. "Please."

"Later," his father said. "Clown's . . . taking a rest, that's all. He'll be back in no time at all.

And you, my boy, probably want something to eat or drink, don't you?"

"Where's mother?"

"She's . . ." His father paused. "She can't be here right now, Schuyler, but she sends her love."

He watched one of the other men touch his father's arm. "He'll be safer with the other kids, Titus, in the main creche."

"He isn't like one of the other kids," his father said.

Now they were ushering him out, into the cold. The corridor beyond the nursery plunged into darkness in either direction, away from the little pool of light defined by the adults' torches.

"What happened?" Sky said, realising for the first time that it was not just his own microcosm that had been upset; that whatever had happened had touched the world of the adults as well. He had never seen the ship like this before.

"Something very, very bad," his father said.

FIVE.

I came crashing out of the dream of Sky Haussmann and for a moment thought I was still inside another dream, one whose central feature was a terrifying sense of loss and dislocation.

Then I realised it wasn't a dream at all.

I was wide awake, but it felt as if half my mind was still sound asleep: the part that held memory and identity and any comforting sense of how I had ended up where I now found myself; any threadlike connection to the past. What past? I expected to look back and at some point to encounter sharp details-a name; a hint of who I was-but it was like trying to focus on grey fog.

Yet I could still name things; language was still there. I was lying on a hard bed under a thin brown, knitted blanket. I felt alert and rested-and at the same time completely helpless. I looked around and nothing clicked; there was not the slightest tinge of familiarity on any level. I held my hand in front of my face, studying the ridge-lines of veins on the back of it, and it looked only slightly less strange.

Yet I remembered the details of the dream well enough. It had been dazzlingly vivid; less theway a dream ought to be-incoherent, with shifting perspectives and haphazard logic-than a strictly linear slice of documentary. It was as if I had been there with Sky Haussmann; not seeing things from exactly his point of view, but following him like an obsessive phantom.

Something made me turn my hand over.

There was a neat rust-spot of dried blood in the middle of my palm, and when I examined the sheet beneath me, I saw more freckles of dried blood, where I must have been bleeding before I woke up.

Something almost solidified in the fog; a memory almost assuming definition.

I got out of the bed, naked, and looked around me. I was in a room with roughly shaped walls-not hewn from rock, but formed from something like dried clay, painted over with brilliant white stucco. There was a stool adjacent to the bed and a small cupboard, both made from a type of wood I didn't recognise. There was no ornamentation anywhere except for a small brown vase set into an alcove in one wall.

I stared at the vase in horror.

There was something about it that filled me with terror; terror that I knew instantly to be irrational, but couldn't do anything about. So maybe there is some neurological damage, I heard myself say-you've still got language, but there's something deeply screwed up somewhere in your limbic system, or whatever part of the brain handles that old mammalian innovation called fear. But as I found the focus of my fear, I realised it wasn't actually the vase at all.

It was the alcove.

There was something hiding in it: something terrible. And when I realised that, I snapped.

My heart was racing. I had to get out of the room; had to get away from the thing that I knew made no sense, but which was still turning my blood to ice. There was an open doorway at one end of the room, leading "outside'-wherever that was.

I stumbled through it.

My feet touched grass; I was standing on a patch of moist, neatly cut lawn surrounded on two sides by overgrowth and rock. The chalet where I'd woken was behind me, set into a rising slope, with the overgrowth threatening to lap over it. But the slope simply kept on rising; assuming an ever-steepening angle-reaching vertical and then curving over again in a dizzying verdant arc, so that the foliage resembled Chinese spinach glued to the sides of a bowl. It was difficult to judge distance, but the world's ceiling must have been about a kilometre over my head. On the fourth side, the ground dropped away a little before resuming its climb on the opposite side of a toylike valley. It rose and rose and met the ground which climbed behind me.

Beyond the overgrowth and rock on either side of me, I could just make out the distant ends of the world, blurred and blued by the haze of intervening air. At first glance, I seemed to be in a very long cylinder-shaped habitat, but that wasn't the case: the sides met each other at either end, suggesting that the overall shape of the structure was that of a spindle: two cones placed back to back with my chalet somewhere near the point of maximum width.

I racked my memory for knowledge of habitat design and came up with nothing except the nagging sense that there was something out of the ordinary about this place. There was a hot blue-white filament running the length of the habitat; some kind of enclosed plasma tube which must have been able to be dimmed and shaded to simulate sunset and darkness. The greenery was enlivened and counterpointed by small waterfalls and precipitous rockfaces, artfully arranged like details in a Japanese watercolour. On the far side of the world I saw tiered, ornamental gardens; a quilt of different cultivations like a matrix of pixels. Here and there, dotted like white pebbles, I saw other chalets and the occasional larger hamlet or dwelling. Stone roads meandered around the valley's contours, linking chalets and communities. Those near the endpoints of the two cones were closer to the habitat's spin axis and the illusion of gravity must have been weaker there. I wondered if the need for that had been a driving force in the habitat's design.

Just as I was beginning to seriously wonder where I was, something crept out of the undergrowth, picking its way into the clearing via an elaborate set of articulated metal legs.

My hand shaped itself around a nonexistent gun, as if, on some muscular level, it had expected to find one.

The machine came to a halt, ticking to itself. The spider legs supported a green ovoid body, featureless except for a single glowing blue snowflake motif.