INCOMERS

Paul J. McAuley

Of the three friends had seen the man in one of the malls or plazas of the new city, they wouldn't have spared him a second glance, but in the old part of Xamba, the largest city on Saturn's second-largest moon, where the weird was commonplace and the commonplace weird, he was as exotic as a tiger strolling down Broadway ii old New York. People born and raised in the weak or nonexisent gravity of the various moons, orbital habitats, and ships of the niter reaches of the solar system—Outers—were generally taller han basketball stars and skinny as rails, and most citizens of old Kamba were of pale-skinned, blond, blue-eyed Nordic stock. This Tian, with a compact build, a shaven head, a neatly pointed black beard, and skin the color of old teak, was definitely no Outer. So why was he sitting at a tiny stall near the bottom of the produce market's spiral walkway, a place where most incomers never ventured, selling bundles of fresh herbs and various blends of herb tea?

Jack Miyata said that he was probably a harmless eccentric; Mark Griffin was convinced that he was some kind of exiled pervert or criminal; Sky Bolofo, who had filled the quantum processor of his large, red-framed spex with all kinds of talents and tricks, used face-recognition program to identify the fellow, then pulled up his public page.

"His name is Algren Rees. He lives right here in the old city. He sells herbs and he also fixes up pets."

Jack said, "Is that it? No links to family or friends or favorit s?" Sky shrugged.

"He has to be hiding something," Mark said. "What about t his private files?"

"No problem," Sky said complacently, but ran into h avy security as soon as he tried to hack into Algren Rees's passw )rd-protected files, and had to back out in a hurry.

Jack suggested that he could be a retired spy—just before the Quiet War kicked off, all of the Outer Colonies had been lousy with spies masquerading as diplomats and businesspeople—and Mark jumped all over the idea.

"Maybe he's still active," he said. "Selling herbs is his cc ver. What he's actually doing is gathering information. Keeping watch for terrorists and so-called freedom fighters."

Sky, his fingers pecking at the air in front of his face, using his spex's virtual keyboard to erase his electronic trail in case Algren Rees's security followed it, said that if the fellow wanted real cover, he should have made himself taller and skinnier, which cracked up the other two. They were all the same age, fourteen, and went to the same school and lived in the same apartment complex in the new part of Xamba. They were also Quiet War buffs who restaged campaigns, sieges, and invasions on a war-gaming network, which was how Jack had hooked up with the other two. Jack Miyata ha moved to Xamba, Rhea, just two months ago. Unlike most city-states in the Saturn system, Xamba had remained neutral during the Quiet War. After the war had ended in defeat for every one of the rebellious Outer Colonies, Earth's Three Powers Alliance had settled the bulk of its administration there, building a new city of towers and domes above Xamba's underground chambers. Seven years later, New Xamba was still growing—Jack's engineer parents were involved in the construction of a thermal-exchange plant that would tap the residual heat of the little moon's rocky core and provide power for a brand-new sector. Very few incomers from Earth ever ventured beyond their apartment complexes, malls, and leisure parks, but Jack had caught the exploration bug from his parents. He'd roamed through much of the old and new parts of Xamba, and after passing a pressure-suit training course had taken several long hikes through the untouched wilderness in the southern half of the big crater in which the city was located and from which it took its name, had climbed to the observatory at the top of the crater's central peak, and had visited the memorial at the crash site of a spaceship that had attempted to break the blockade during the war. It had been Jack's idea to take his two new friends to his latest discovery, the produce market in the oldest chamber of old Xamba. As far as Jack was concerned, the market was a treasure house of marvels, but as they'd wandered between stalls and displays of strange flowers and fruits and vegetables, streamers of dried waterweed, tanks of fish and shrimp, caged birds and rats, and bottle vivariums in which stag beetles lumbered like miniature rhinoceroses through jungles of moss and fern, Mark and Sky quickly made it clear that they thought it was smelly, horribly crowded with strangely dressed, alarmingly skinny giants, and, quite frankly, revoltingly primitive. When food makers could spin anything from yeast and algae, why would anyone want to eat the meat of real live animals, especially as they would have to kill them first? Kill and gut them and God knew what else. But all three agreed that there was definitely something intriguing about the herb seller, Algren Rees.

"Maybe he's a double agent," Jack said. "He's in the pay of the Three Powers, but he's gone over to the Outers, and they're using him to feed our side false information."

Mark nodded. "There's plenty of people who want to sabotage the reconstruction. Look at that blowout at the spaceport last month."

"The newsfeeds said it was an accident," Sky said. "Someone fitted some kind of widget upside down or the wrong way round."

"Of course they said it was an accident," Mark said scornfully.

"It's the official line. But it doesn't mean it really was an accident.'

He was a stocky boy who, with his pale skin, jet-black hair, and perpetual scowl, looked a lot like his policeman father. His mother was in the police too, in charge of security at the spaceport. He had a vivid imagination and an opinion about everything.

Jack wanted to know if Mark had inside information about the accident, and Mark smiled and said that maybe he didn't and maybe he did. "I had a feeling there was something wrong with Mr. Algren Rees as soon as I saw him. All good police have what I call gut instinct, and my gut very definitely told me that this fellow is a wrong one, and Sky's run-in with his over-the-top security confirmed it. It's up to all of us to find out exactly who he is, and why he's living here. It's our duty."

Jack and Mark quickly decided that they would follow Algren Rees—or "Algren Rees" as Mark called him, drawing quotation marks in the air with his little finger—and made Sky promise that lie would use his data miners to ferret out anything and everything about the man. They were fourteen years old, secret masters of all hey surveyed, possessed by restless energies and impulses that war gaming was no longer enough to satisfy, and hungry for adventure, for anything that would fill up the desert of the school holidays. Following Algren Rees and uncovering his secrets was just the beginning. Algren Rees had no fixed routine. He spent only an hour or so at his stall in the produce market (which explained why Jack hadn't seen him there before); he tended the little garden where he grew his herbs; he sat outside the door of his apartment, a one-room efficiency on a terrace directly above the market, drinking tea or homemade lemonade and watching people go by; he took long, rambling walks through the old city. Jack saw more of the place in the three days he spent following the man, sometimes with Mark, sometimes on his own, than he had in the past two months.

The cylindrical chambers of old Xamba were buried inside the rock-hard water ice of the crater's eastern rimwall like so many bottles in a snowbank, and most had transparent endwalls facing what was generally reckoned to be one of the most classically beautiful views on all of Saturn's family of moons, across slumped terraces and flat, dusty plains toward the crater's central peak, which stood right at the edge of the close, curved horizon. In the little moon's microgravity, just 3 percent of Earth's, there was little difference between horizontal and vertical. Inside the old city's chambers, apartments, shops, cafes, workshops, and gardens were piled on top of each other in steep, terraced cliffs, rising up on either side of skinny, landscaped parks and canals in steep-sided troughs. Apart from the boats in the canals that linked the chambers, traffic was entirely pedestrian. Jack had no problem blending into the crowds as he trailed Algren Rees through markets and malls, parks and plazas, up and down ropeways, chutes, and chairlifts. Although Mark insisted on teaching him some basic tradecraft (he claimed to have learnt it from his parents, but more likely had gotten it from some text), Jack figured out most of his moves for himself. Staying well behind his quarry and trying to anticipate his every move, walking straight past him or dodging up a ropeway or down a chute if he stopped to talk to someone, lurking inconspicuously when he lingered over a bulb of coffee at a cafe or a tube of beer at a bar. It was a lot more exciting than any war game, and a lot scarier, too. There was no wizard to ask for a clue or hint about what to do next, every decision was unconditionally permanent, and any mistake would be his last, game over. But Algren Rees seemed quite unaware that he was being followed, and by the third day Jack plucked up the courage to chat with the woman behind the counter of the café where the man ate his lunch and breakfast, learning that he had moved to Rhea two years ago and that he was originally from Greater Brazil, where he'd worked in the emergency relief services as a paramedic and helicopter pilot. He seemed well liked. He always stopped to talk to his neighbors when he met them as he went about his errands, and had long conversations with people who bought herbs or herb tea at his stall. He was a regular at the cafe and several bars in various parts of the city, trading fresh herbs for food and drink, and apart from eating out, his life seemed as austere as any monk's. Still, Jack didn't see how he could stretch the minuscule income from his market stall and fixing broken pets to cover the rent on his apartment, and his power and water and air taxes.

"I guess he must have some kind of private income," Jack said to Mark.

"He has secrets, is what he has," Mark said. "We don't even know if 'Algren Rees'"—he did the thing with his little fingers—"is his real name, no thanks to Sky for bailing on us. Some hacker he turned out to be, when it came down to it."

"He was majorly spooked when he ran up against our friend's electronic watchdogs," Jack said.

"Which also proves our friend has something to hide, or why else would he be using military-grade security?"

It was late in the evening. The city's sky lighting was beginning to dim. The two boys were sitting in a little park near the top of the east side of the chamber, taking turns with a pair of binoculars to keep watch on Algren Rees's apartment, which was near the top of the west side. Across the wide gulf of air, the man was sitting on the little raised porch outside his front door, wearing shorts and nothing else and reading a book. Books printed on paper were a quirky tradition in old Xamba. Algren Rees read slowly, licking the top of his thumb before turning each page. Yellow light from inside the apartment spilled around him. Pretty soon, judging by the last three days, Algren Rees would turn in. He wasn't a night owl.

"What we need to do," Mark said, "is take this to the next level." Jack felt a tingling rush of anticipatory excitement. "What do you mean?"

"I mean we have to get into his apartment."

"You're kidding."

Mark had a determined look, a just of hi sheavy jaw like a dog gripping a bone it isn't willing to let go of. "It's what real spies would do. I bet he has all kinds of stuff stashed away in there. Stuff that would crack this case wide open."

"He probably has all kinds of security, too," Jack said. "Oh, I can handle that."

"Right."

"It's simply a matter of police tradecraft," Mark said.

"Right."

"I'd like to tell you more, but if I did, I'd have to kill you afterward," Mark said. Like his father, he never smiled when he made a joke. They decided to do it the very next day, even though it was a Monday, the one day in the week when the produce market was closed, when Algren Rees wouldn't be safely occupied at his stall for an hour or so. Jack would find some way of keeping the man at the cafe where he ate breakfast; meanwhile, Mark would break into the apartment, to see what he could see.

It wasn't much of a plan, but Jack couldn't think of anything better. He was pretty sure that Algren Rees wasn't any kind of spy, but he'd developed a curious feeling of kinship with the man during the time he'd spent trailing him around the chambers of old Xamba. Yet although he'd spent a couple dozen hours in his company, he still knew almost nothing about him. It had become a matter of pride to find out who Algren Rees really was, and why he had chosen to come here, and live amongst the Outers.

When they met up early the next morning, Mark wanted to know what was in the box Jack was clutching to his chest. Jack told him that it was a foolproof way of keeping the man busy.

"I'll tell you what it is it if you tell me how you are going to break into his apartment."

"I'm not going to break in, Mark said with a sly smile. "Are you sure you can keep him busy for half an hour ?"

"Absolutely," Jack said, tapping the top of the plastic box, feeling what was inside stir, a slow, heavy movement that subsided after a moment. Actually, he wasn't sure at all. He'd slept badly, his mind spinning, tracing and retracing every part of a plan that seemed increasingly silly and flimsy. Two hours later, when Algren Rees finally left his apartment and he followed him to the cafe, the muscles of Jack's legs felt watery and his stomach was doing somersaults. But it was too late to back out. As Jack skimmed up a short ropeway to the cafe, he knew that Mark would be breaking into the apartment. The cafe was little more than a bamboo counter in the shade of a huge fig tree, with half a dozen stools, a hot plate, and a hissing coffee machine that the owner, a very tall, incredibly skinny woman with long snow-white hair, had built herself, using a design centuries old. The food was prepared from whatever was in season in the garden spread on either side of the fig tree, and whatever came in trade—the citizens of old Xamba had a complicated economy based on barter of goods and services.

It was the middle of the morning. Algren Rees and Jack were the only customers. Jack set the plastic box on the counter and asked the owner for an orange juice, then turned to the man and said as casually as he could manage that he'd heard that he treated sick pets.

"Who told you that?"

Algren Rees, hunched over a bowl of porridge flecked with nut and seeds, didn't look up when he spoke. He had a husky voice and I a thick accent: the voice of a villain from some cheap virtuality.

"She did," Jack said, nodding to the owner of the cafe, who was filling a blender with orange segments and a handful of straw berries.

"I guess I did," the woman said with cheerful carelessness, and switched on the blender. She'd braided her hair into a pigtail that twitched down her back as she moved about in the narrow space behind the counter.

"Stop by my apartment when you've had your breakfast," Algren Rees told Jack.

"It's just around the corner, down the ropeway, past a clump of black bamboo. The one with the red door."

He was eating his porridge slowly but steadily. In a few minutes he would be finished. He'd walk back to his apartment, find that red door open ... Jack pushed the box an inch along the counter and said, "I have it right here."

"So I see," Algren Rees said, although he still hadn't looked up. "And I have my breakfast right here, too."

"It belongs to my little sister," Jack said, the little lie sliding out with surprising ease. He added, "She loves it to bits, but we're scared that it's dying."

"Why don't you take a look, Al," the woman said as she placed the bulb of orange juice in front of Jack. "The worst that can happen is that it'll improve your karma."

"It will need much more than fixing a pet to do that," Algren Rees said, smiling at her.

The woman smiled, too, and Jack was reminded of the way his parents shared a private joke.

"All right, kid," Algren Rees said. "Show me what you got." It was a mock turtle, a halflife creature that produced no waste or unpleasant odors and needed only a couple of hours of trickle charge and a cupful of water a day. It had large, dark, soulful eyes, a soft yellow beak, a shell covered in pink fur, and a fifty-word vocabulary. Although it didn't belong to Jack's wholly imaginary little sister but to the youngest daughter of Jack's neighbors, it really was sick. It had grown slow and sluggish, its fur was matted and threadbare, its eyes were filmed with white matter, and its breath was foully metallic.

Algren Rees studied it for a moment, then took a diagnostic pen from one of the many pockets of his brocade waistcoat, lifted the mock turtle from the box and turned it upside down, and plugged the instrument into the socket behind its front leg.

"Tickles," the turtle complained, working its stubby legs feebly.

"It's for your own good," Algren Rees told it. "Be still." He had small, strong hands and neatly trimmed fingernails. There were oval scars on the insides of his wrists; he'd had neural sockets once upon a time, the kind that interface with smart machinery. He squinted at the holographic readout that blossomed above the shaft of the diagnostic pen, then asked Jack,

"Do you know what a prion is?"

Jack's mind went horribly blank for a moment; then a fragment of a biology lesson surfaced, and he grabbed at it gratefully. "Proteins have to fold up the right way to work properly. Prions are proteins that fold up wrongly." Algren Rees nodded. "The gene wizard who designed thesethings used a lot of freeware, and one of the myoelectric proteins has a tendency to turn prions. That's what's wrong with your sister's pet. It's a self-catalyzing reaction—do you know what that means?"

"It spreads like a fire. Prions turn ordinary proteins into more prions." Algren Rees unplugged the diagnostic pen and settled the mock turtle in the box. "The myoelectric proteins are what powers it. When they fold the wrong way they can no longer hold a charge, and when enough have folded wrongly, it will die."

"Can you fix it?"

Algren Rees shook his head. "The best thing would be to put it to sleep." He looked genuinely sorry, and Jack felt a wave of guilt pass through him. Right now, Mark was breaking into the man's apartment, rifling through his possessions ...

"If you like, I can do it right now," Algren Rees said. "I'll have to tell my sister first."

Algren Rees shrugged and started to push away from the counter, saying, "I'm sorry I couldn't help you, kid."

"Wait," Jack said desperately, knowing that Mark must still be in the apartment. Adding, when Algren Rees looked at him, "I mean, I want to ask you, why is someone like you living here?"

"Why does who I am have anything to do with where I live?" There was a sudden sharpness in the man's voice.

"Well, I mean, you're an incomer. From Earth," Jack said, feeling the heat of a blush rise in his face. "And incomers, they all live in the new city, don't they? But you live here, you sell herbs .. ."

"You seem to know an awful lot about me, kid. Why the interest?"

"I saw you at the produce market," Jack said, blushing harder, certain that he'd been caught out.

Algren Rees studied him for a moment, pinching the point of his neat black beard between finger and thumb. Then he smiled and said, "I had the feeling I'd seen you before. You like the market, huh?"

"It's one of my favorite places in the old city."

"And you like the old city?"

Jack nodded.

"Most incomers don't much care for it."

Jack nodded again.

"So maybe we have something in common, you and I. Think about it, kid," Algren Rees said. "If you can figure it out, stop by my stall sometime. But right now I have an appointment to keep."

The woman behind the counter asked him to have a good thought on her behalf, and then he was skimming away. Not toward his apartment, but in the opposite direction, toward the chute that dropped to the floor of the chamber. Jack didn't dare ask the woman (who refused his offer to pay for his juice, telling him that he could bring her some sour oranges next time he visited the produce market) where Algren Rees was headed, who he was going to meet. As he set off after the man, he called Mark, told him about the conversation, told him that he believed that Algren Rees was going to meet someone. Mark said that he'd catch up, and ten minutes later arrived breathless and excited at the canalside jetty just as Algren Rees was climbing into one of the dinghies that ferried people around the city's waterways.

"He's a spy, all right," he told Jack.

"You found something. What did you find?"

Mark patted the pouch of his jumper. "I'll show you after we get going." There were several high-sided dinghies waiting at the jetty. Jack and Mark jumped into one, and Mark stuck something in a slot in the fat sensor rod that stuck up at its prow and ordered it to follow the boat that had just left.

As their dinghy headed toward the tunnel that linked the chamber with its neighbor, rising and falling on the tall, sluggish, low-gravity waves that rolled along the canal, Jack said, "That's how you got into his apartment, isn't it? You used that card on the lock."

He was sitting in the stern, the plastic box with the mock turtle inside it on his knees.

Mark, standing at the prow with one hand on top of the sensor rod, said, "Of course I did."

"I suppose you stole it."

"No one stole anything," Mark said. "I borrowed my mother's card last night, and Sky cloned it."

"If she finds out—"

"As long as I don't get into trouble, my parents don't care what I do. They're too busy with their jobs, too busy advancing their careers, too busy making money," Mark said. He had his back to Jack, but Jack could hear the bitterness in his voice. "Which is fine with me,

because once they make enough, we'll leave this rotten little ball of ice and go back to Earth."

There was a short silence. Jack was embarrassed, feeling that he'd had an unwanted glimpse of his friend's true feelings through a crack in his armor of careless toughness. At last, he said, "If we

prove that Algren Rees really is a spy, your parents will be proud of you." Mark turned around and said carelessly, "Oh, he's a spy, all right. Guess what I found in his apartment?"

It was the kind of question you were bound to fail to answer correctly, so Jack shrugged.

Mark, smiling a devilish smile, reached into the pouch of his jumper and drew out a small silvery gun.

Jack was shocked and excited. "Is it real?"

"Of course it is. And it's charged, too," Mark said, pointing to a tiny green light that twinkled above the crosshatched grip.

He explained that it was a railgun that used a magnetic field to fire metal splinters tipped with explosive or toxin, and showed Jack the Navy sigil stamped on top of its reaction chamber.

"If he's a spy, why does he have a Navy sidearm?" Jack said.

"Maybe he was in the Navy before he became a spy. Or he killed someone in the Navy, and kept this as a souvenir," Mark said.

Discovering the gun had made him bold and reckless. He talked about catching Algren Rees in the middle of some act of sabotage, about arresting him and forcing him to tell everything about the conspiracy in which he was clearly involved.

Although Jack was excited, too, he could see that his friend was getting carried away. "This doesn't change our plan," he said. "We follow the man and see what he gets up to, and then we decide what to do." Mark shrugged and said blithely, "We'll see what we'll see."

"We shouldn't just charge in," Jack said. "For one thing, if he really is a spy, he's dangerous. Spies were hardwired with all kinds of wild talents."

"If you're scared, you can get off the boat anytime you want."

"Of course I'm not scared," Jack said, even though he was, more than he cared to admit. "All I'm saying is that we have to be careful." Algren Rees's dinghy stopped three times, dropping people off and picking up others, before it headed down a long transparent tunnel, with Mark and Jack's dinghy following a couple hundred meters behind it. The tunnel was laid along the edge of a steep cliff, with a stunning view of the crater. It was the middle of Rhea's night. Saturn hung full and huge overhead in the black sky like God's own Christmas ornament, the razor-thin line of his rings stretching out on either side of his banded face, his smoggy light laid across terraced icefields. Jack leaned back, and for the ten minutes it took to traverse the tunnel was lost in wonder at the intricate beauty of the gas giant's yellow and dirty-white and salmon-pink bands, their frills and frozen waves, forgetting all about the gun in Mark's pouch, forgetting all about following Algren Rees.

At the end of the tunnel, the canal entered a skinny lake pinched between two steep slopes of flowering meadows and stands of trees and bamboos. It was the city's cemetery, where bodies were buried in soil and trees planted over them, so that their freight of carbon and nitrogen and phosphorous and other useful elements could reenter the loop of the city's ecosystem. It was a quiet, beautiful place, artificially lit in the even golden tones of a late summer afternoon. On one steep slope was the black pyramid, hewn from crystalline iron mined from the heart of an asteroid, that commemorated those who had died in accidents during the construction of the old city; on the other was a slim white column topped by an eternal blue flame, the monument to the citizens of Xamba who had been killed during the Quiet War. For although

:he city had remained neutral, more than a thousand of its citizens had died because they'd been trapped in sieges in rebellious cities, or n ships crippled by neutron lasers, microwave bursters, and EMP mines. Apart from these two monuments, and the bone-white paths that wandered here and there, the woods and meadows seemed untouched by human hands, a tame wilderness where birds and cat-sized deer and teddy bear—sized pandas roamed freely. Algren Rees and two women disembarked at a jetty of black wood with a red-painted Chinese arch at one end. The two women went off along the lakeshore; Algren Rees started up a steep path that bent around a grove of shaggy cypress trees. As soon as their dinghy nudged the jetty, Mark sprang out, bounded through the arch, and set off up the path after Algren Rees. Jack had to hurry to catch up with him. They went around the cypress grove, climbed a ropeway alongside a tiny stream that ran over white rocks speckled with chunky black shards of shock quartz, followed Algren Rees as he cut through a belt of pines.

Beyond the trees, a lumpy heath of coarse tussock grass and purple heather and clumps of flowering gorse rose in steep terraces to meet the edge of the chamber's curved blue roof. The flame-topped white column of the monument to Xamba's war dead stood halfway between the pines and the painted sky. Algren Rees stood in front of it, still as a statue, his bald head bowed. Crouched behind a pine tree, Jack and Mark discussed what they'd do when Algren Rees's coconspirator appeared, agreeing that they might have to split up, follow the men separately, and meet up again later. But no one came. Big silver and gold butterflies tumbled over each other above a clump of gorse; rabbits emerged from their burrows and began to nibble at the grass. At last, Algren Rees turned from the monument and moved on up the slope, silhouetted against the solid blue sky for a moment when he reached the top, then dropped out of sight.

Rabbits leaped away in huge, graceful arcs as Jack and Mark followed the man. Jack still hadn't quite mastered the art of moving quickly in low gravity, and Mark outpaced him at once, making a bounding run up the rough slope, disappearing between rocks spattered with orange lichens. Jack hauled himself through the rocks, discovered a narrow stairway down to the floor of a narrow gully, and saw Algren Rees and Mark facing each other in front of a steel door set in a wide frame painted with yellow-and-black warning chevrons—the entrance to an airlock. Mark was pointing the pistol at Algren Rees's chest, but the stocky man was ignoring him, looking instead at Jack as he came down the stairs, saying mildly, "Tell your friend he has made a mistake."

"Kneel down," Mark said. He was wavering like a sapling in a high wind, but he held the pistol steady, bracing his right wrist with his left hand. "Kneel down and put your hands on your head."

Algren Rees didn't move, saying, "I believe that is mine. How did you get it?"

"Just kneel down."

"I must suppose that you broke into my apartment while your friend"—he looked at Jack again, a sharp, unfriendly look—"kept me busy. What is this about?

What silly game are you playing?"

"It's no game," Mark said. "We know you're a spy." Algren Rees laughed.

"Shut up!"

Mark screamed it so loudly it echoed off the blue sky curving overhead. Jack, clutching the plastic box to his chest, frightened that his friend would shoot Algren Rees there and then, said, "You said that you had an appointment with someone. Who is it?"

"Is that what this is about? Yes, I visit someone. I visit her every Monday. Everyone knows that." Algren Rees looked at Mark and said, "Hand over the pistol, kid. Give it to me before you get into trouble."

"You're a spy," Mark said stubbornly. "I'm arresting you. Kneel down—" There was a blur of movement, a rush of air. Mark was knocked into Jack, they both fell down, and Algren Rees was standing a yard away, the pistol in his hand. He was sweating and trembling lightly all over, like a horse that had just run the hardest race of its life. He stared at the two boys, and Jack felt a spike of fear cleave right through him, thinking that the man was going to shoot them and dump their bodies in some deep crevasse outside. But then the man tucked the pistol in the waistband of his shorts and said, "My nervous system was rewired when I was in the Navy. A long time ago, but it still works. Go home, little boys. Go back to your brave new city. Never let me see you again, and I won't tell anyone about this. But if I find you following me again, I will have a long hard talk with your parents, and with the police, too. Go!"

Jack and Mark picked themselves up, and ran.

On the boat ride back, Mark vented his anger and fear and shame by making all kinds of plans and boastful threats. He promised vengeance. He promised to find out the truth. He promised to bring the man to justice. He told Jack that if he said so much as one word about this, he'd get into so much trouble he'd never find his way out again.

Jack, with the cold clarity that fear sometimes brings, told Mark that he was being a fool. Even if Algren Rees was a spy, there was nothing they could do about it because they were outside the law, too. If they went to the police, how were they going to explain that they'd broken into his apartment, stolen his gun, and threatened him with it?

"If he's a spy?" Mark said. "The gun proves he's a spy!"

"Does it? The gun is a Navy sidearm—you showed me the sigil yourself. And he said that he was in the Navy."

Mark sneered. "I suppose you believe him."

"And if he really was a spy, he would have shot us after he took it back."

"Yes, and he used some kind of wild talent to take it back. He speeded up. Which also proves that he's a spy."

"He took his own gun back, Mark. The gun you stole from his apartment. And we can't do anything about it because he threatened to go to our parents."

"It's an empty threat," Mark said stubbornly. "He can't go to our parents, or to the police, either, because if he did, it would blow his cover. It's a deadlock, don't you see? And we have to figure out how to turn it to our advantage."

Jack couldn't get Mark to promise that this was an end to it, nd spent the next few days in a misery of fear and guilty anticipation. He avoided his parents as much as he could, either hiding away in his room, halfheartedly fiddling with his virtual model of the Invasion of Paris, Dione (but after his adventure had gone so badly wrong, playing at soldiers no longer had the appeal it once did), or mooching around the apartment complex's mall. That was where he met Sky Bolofo. Sky wanted to know what had made Mark so terminally pissed off with Algren Rees, and eventually got Jack to confess everything.

"Wow. You're lucky the guy didn't report you," Sky said when Jack was finished.

"I know," Jack said. "The problem is, Mark still thinks he's some kind of spy. I think he's going to do something stupid."

They were sitting in the mall's food court. The chatter of the people around them rose through the fronds of tall palms toward he glass dome. Sky studied Jack through his red-framed spex and said, "I think so, too."

"You do? What's Mark been saying?"

That was when Jack learned that their friend had told Sky that he was going to settle things once and for all, and had asked for Sky's help. Sky told Jack, "I said good luck, but it was nothing to do with me." And then,

"Hey, where are you going?"

"I have to settle something, too," Jack said. He tried to phone Mark, but Mark was screening his calls and wouldn't answer his door when Jack went to his apartment. But by then Jack had more or less worked out what Mark was planning to do. Each and every Monday, Algren Rees had a mysterious appointment. And Jack and Mark had confronted him at the entrance to an airlock, which meant that it was probably somewhere outside the city, on the surface .. .

Jack knew that he couldn't tell either his parents or Mark's parents about what had happened, and what he believed Mark was planning. He was just as guilty as Mark, and would get into just as much trouble. He'd have to sort it out himself, and because Mark was refusing to talk to him, he'd have to catch him in the act, stop him before he did something really dumb. When he asked Sky to help him out, Sky naturally refused at first, just as he'd refused to help Mark, but quickly changed his mind when Jack reminded him that if Mark was caught, everything would come out, including the police card that Sky had cloned. After Jack explained what he thought Mark was planning to do, Sky said that in the three years he'd been living in New Xamba, he'd never once stepped outside and didn't intend to break that record now, but he could download a hack into Jack's spex that would give him full access to the city's CCTV system so that Jack could use it to follow Mark wherever he went.

"I'll patch in a demon with a face-recognition program. It'll alert you if Mark gets anywhere near an airlock. And that's all I'm doing. And if anyone asks you where you got this stuff, tell them it's freeware."

"Absolutely," Jack said. "I know all of this is my fault. If I hadn't taken him to the market, and agreed that there was something funny about the guy selling herbs—"

"Don't beat yourself up," Sky said. "Mark would have got into trouble all by himself sooner or later. He's bored, he hates living here, and he doesn't exactly get on with his parents. It's quite obvious that this whole thing is some kind of silly rebellion."

"You hate living here, too," Jack said. "But you didn't break into someone's apartment and steal a gun."

"I don't much care for the place," Sky said, "but as long as I'm left alone to get on with my own thing, it doesn't matter where I live. Mark, though, he's like a tiger in a cage. Be careful, Jack. Don't let him get you into any more trouble."

The demon woke Jack in the early hours of Monday morning. He fumbled for his spex, shut off the alarm, stared dazedly at a skewed video picture of Mark sitting in a dressing frame that was assembling a pressure suit around him, then realized with a surge of adrenaline that this was it. That Mark really was going through with it.

The main airlocks of the apartment complex were in an ancillary structure reached by a long, slanting tunnel. Mark was long gone by the time Jack reached it, but despite his bladder-burning need to follow his friend, Jack remembered his training. When you went out onto the airless surface, even the slightest oversight or equipment malfunction could be deadly. Once the dressing frame had fitted him with a pressure suit, he carefully checked the suit's power systems and lifesystem, and because he didn't know how long he was going to be outside, took time to hook up a spare air pack before making his way through the three sets of doors.

The outer door of the airlock opened onto a flat, dusty apron trodden everywhere with cleated bootprints, reminding Jack of the snow around the ski lifts at the mountain resort where he and his parents had several times gone on holiday. Inside the city, which kept Earth time, it was six in the morning; outside, it was the middle of Rhea's 108-hour-long day. Saturn's slender crescent was cocked overhead, lassoed by the slender ellipse of his rings. The sun was a brilliant diamond whose cold light gleamed on the towers and domes of the new city and the great curve of the rimwall behind them. Although the rimwall was more than three miles away, the sculpted folds of its cliffs and its gently undulating crest stood sharp and clear against the black, airless sky.

Jack tried and failed to pick up the radio transponder of Mark's pressure suit—Mark must have switched it off, but that didn't matter, because Jack knew exactly where his friend was going. He walked around the side of the airlock to the racks where the cycles were charging, and found to his surprise that every rack was occupied. Then he realized that Mark, like most incomers, had never taken a pressure-suit training course (he must have used the cloned police card to force the dressing frame to fit him with a suit) and had never before taken a single step outside the city, so there was no reason why he should know about the cycles.

They were three-wheeled, with fat, diamond-mesh tires, a low-slung seat, and a simple control yoke. Jack pulled one from the rack, clambered onto it, and, feeling a blithe optimism, set off toward the cemetery chamber at the eastern end of the old city. He was on a cycle, and Mark was on foot. It was no contest.

He followed a polymer-sealed track that, throwing wide loops around cone-shaped rockfalls, cut through the fields of boulders that stretched out from the base of the rimwall's steep cliffs. He drove slowly, scanning the jumbled wilderness, and after ten minutes spotted a twinkle of movement amongst the tan boulders and ink-black shadows. He stopped the cycle, used the magnification feature of his visor, and saw a figure in a white pressure suit moving in a kind of slow-motion kangaroo hop. Jack plotted a course and drove half a mile along the track before turning toward the cliffs, intending to intercept Mark when he reached the cemetery chamber's airlock. The going was easy at first, with only a few outlying boulders to steer around, but then the ground began to rise up and down in concentric ridges like frozen waves, and the rubble fallen from the cliffs grew denser, tumbled blocks of dirty ice of every size, some as big as houses, all frozen harder than granite. Jack kept losing sight of Mark, and piled on the speed in the broad dips between the ridges, anxious that he'd lose sight of him completely. To his left, the rumpled plain of the crater floor stretched away toward the central peak; to his right, the lighted circles of the endwalls of the old city's buried chambers glowed with green light in the face of the rimwall I Ifs, like the portholes of a huge ocean liner or the windows of a giant's aquarium. He was driving toward the crest of the fifth or sixth ridge when the razor-sharp, jet black shadow between two shattered blocks turned out to be a narrow but deep crevice that neatly trapped the cycle's front wheel. The cycle slewed, Jack hit the brakes, everything tipped sideways with a bone-rattling shock, and hen he was hanging by his safety harness, looking up at the black sky and Saturn's ringed crescent. He managed to undo the harness's four-way clasp and scramble free, and checked the integrity of his pressure suit before he heaved the cycle's front tire out of the crevice. Its mesh was badly flattened along one side, and the front fork was crumpled beyond easy repair. There was no way the machine was going to take him any farther. Well, his suit was fine, he wasn't injured, he had plenty of air and power, and if he got into trouble, he could always phone for help. There was nothing for it. He was going to have to follow Mark on foot. It took two hours to slog four miles across the rough terrain, skirting around huge chunks and blocks, crabbing down uneven slopes into the dips between ridges and climbing back out again, finding a way around jagged crevices. Sometimes Jack glimpsed Mark's pressure-suited figure plodding no more than four or five hundred yards ahead of him, but for most of the time he had only his suit's navigation system to guide him. He was drenched with sweat, his ankles and knees were aching, and he had just switched to his reserve air pack when at last he reached the track that led to the airlock of the cemetery chamber. Jack went slowly through the rubble at the edge of the track, creeping from shadow to shadow, imagining Mark crouched behind a boulder with a gun he'd stolen from his mother or father, waiting for Algren Rees ... But there was no need for caution. Mark's white pressure suit was sprawled on the track just two hundred yards from the airlock, a red light flashing on its backpack. Adrenaline kicked in: Jack reached Mark in three bounds, managed to roll him onto his side. Behind the visor of the suit's helmet, Mark's face was tinged blue, and although his eyes were open, their pupils were fixed and unseeing.

Jack switched on his distress beacon and began to drag Mark's pressure-suited body toward the yellow-painted steel door of the airlock. He was halfway there when the door slid open and a figure in a pressure suit stepped out.

"You kids again," Algren Rees's voice said over the phone link. "I swear you'll be the death of me."

Two days later, after the medivac crew had whisked Mark away to the hospital (when its oxygen supply had run dangerously low, his pressure suit had put him in a coma and cooled him down to keep him alive for as long as possible, but it had been a close thing), after Jack had confessed everything to his parents, Algren Rees took him to see the place he visited each and every week. There was a kind of ski lift that carried them half a mile up a sheer face of rock-hard black ice to the top of the rimwall, and a diamond-mesh path that climbed a frozen ridge to a viewpoint that looked across slopes of ejecta toward a flat, cratered plain. Jack had been there before. He had seen the yard-high steel pillar before, had read the three simple, moving sentences on the plaque set into its angled top, had listened to the brief story its induction loop had played on his pressure suit's phone, the story of how the freighter pilot Rosa Lux had saved Xamba in the last seconds of her life. But even if he hadn't been there, he wouldn't have needed to read the plaque or listen to the looped message; the story was part of the rcason why Algren Rees came here every week.

"She was flying one of those little freelance freighters that are mostly engine, with a tiny internal hold and a cabin not much bigger than a coffin," Algren Rees said. "She was hauling a special cargo' he mayor of the city of Camelot, Mimas. He had been one of the leaders of the rebellion that started the Quiet War. When Camelot fell, he managed to escape, and if he had reached Xamba, he would have been granted political asylum and could have caused all kinds

of trouble.

"I was a singleship pilot, part of the picket which orbited Rhea to prevent ships leaving or arriving. When Rosa Lux's freighter was detected, mine was the only ship able to intercept her, and even then I had to burn almost all my fuel to do it. She was a daring pilot and had come in fast and low, skimming the surface of Rhea just a mile up and using its gravity to slow her so that she could enter into a long orbit and come in to land when she made her second pass. That was what she was doing when my orbit intercepted hers. I had only one chance to stop her, and I made a mess of it.

"I fired two missiles, and both were confused by her countermeasures. One hit the surface; the other missed her ship by a few hundred yards but managed to blow itself up as it zoomed past. It damaged her main drive and changed her vector—her course. She was no longer heading for Xamba's spaceport, but for the rimwall, and the city. I saw her fire her maneuvering thrusters. I saw her dump fuel from her main tank. I saw her sacrifice herself so that she would miss the city. Everything happened in less than five seconds, and she barely missed the top of the rimwall, but miss it she did. And crashed here, and died."

It was early in the morning. The brilliant star of the sun was low in the black sky, throwing long, tangled shadows across the moonscape, but the long scar left by Rosa Lux's ship was clearly visible, a gleaming sword aimed at the eastern horizon.

Algren Rees said, "Rosa Lux had only five seconds to live, and she used that little time to save the lives of a hundred thousand people. The funny thing was, the mayor of Camelot survived. He was riding in a coffin filled with impact gel, cooled down much the same way your friend was cooled down. When the ship crashed, his coffin was blasted free and pinwheeled across the landscape, but it survived more or less intact. The mayor was revived and successfully claimed asylum. He still lives in Xamba—he married a local woman, and runs the city's library. The memorial doesn't tell you that, and there's something else it doesn't tell you, either."

There was silence. Jack watched the scar shine in the new sunlight, waited for Algren Rees to finish his story. He was certain that there would be a moral; it was the kind of story that always had a moral. But the silence stretched, and at last Jack asked the man why he'd come to Rhea.

"After the war, I left the Navy and went back to Greater Brazil, trained as a paramedic, and got on with my life. Then my wife was killed in a train crash. It was more life-changing than the war. I decided to make a last visit to the place where the most intense and most important thing in my life had happened. And soon after I arrived, I fell in love with someone. You have met her, actually."

"The woman who owns the cafe!"

There was another silence. Then Algren Rees said, "You've been here before."

"Sure."

"And I bet it was your idea to visit the produce market."

"I guess," Jack said cautiously, wondering where this was going.

"You're an unusual boy, Jack. Unusual for an incomer, that is. Most of them don't set foot outside the new city. The Three Powers Alliance won the war, but it doesn't know what to do with what it won. That's why it will lose control of it, by and by. And when he Outers realize that, there could be another war. Unless there are more people like you, Jack. Incomers who reach out. Who try to understand the strange moons and habitats of the Outer System. People like you and me. People like Rosa Lux."

"She was an incomer, too?"

"She was born on Earth and moved to Saturn five years before the Quiet War began. The memorial doesn't tell you that because as far as the Outers are concerned, Rosa Lux was one of them. But she was an incomer, just like us.

"I fell in love when I returned to Dione, Jack, and even though it didn't last, I decided to make a home here. But what brought me here to begin with was a chance encounter with another woman—the bravest person I know about. A chance encounter, an instant's decision, can change a single life, or even change history. Perhaps you're too young to know it, but I think something like that has already happened to you."

Jack thought about this, thought about all that had happened in the past week, and realized that his new friend might be right. Time would tell.