If you grew up in Arches, meeting your own future self was no big deal.

The whole point of the place was that from the moment you were born you were trained to fly FTL starships. And everybody knew that an FTL starship was a time machine. Most people figured out for themselves that that meant there might come a day when you would meet a copy of yourself from the future — or the past, depending which end of the transaction you looked at it from.

Pirius, a seventeen-year-old ensign, had always thought of meeting himself as an interesting trial to be faced one day, along with other notable events, like his first solo flight, his first combat sortie, his first sight of a Xeelee, his first screw. But in practice, when his future self turned up out of the blue, it turned out to be a lot more complicated than that.

The day began badly. The bunk bed shuddered, and Pirius woke with a start.

Above him, Torec was growling, “Lethe, are we under attack? — Oh. Good morning, Captain.”

“Ensign.” Captain Seath’s heavy boot had jolted Pirius awake.

Pirius scrambled out of his lower bunk. He got tangled up with Torec, who was climbing down from the upper tier. Just for a second, Pirius was distracted by Torec’s warm, sleepy smell, reminding him of their fumble under the sheets before they had fallen asleep last night. But soon they were standing to attention before Seath, in their none-too-clean underwear.

Seath was a stocky, dark woman, no more than thirty, and might once have been beautiful. But scar tissue was crusted over her brow, the left side of her face was wizened and melted, expressionless, and her mouth drooped. She could have had all this fixed, of course, but Seath was a training officer, and if you were an officer you wore your scars proudly.

Astonishingly, Torec was snickering.

Seath said, “I’m pleased to see part of you is awake, Ensign.”

Pirius glanced down. To his horror a morning erection bulged out of his shorts. Seath reached out a fingernail — bizarrely, it was manicured — and flicked the tip of Pirius’s penis. The hard-on shriveled immediately. Pirius forced himself not to flinch.

To his chagrin, everybody saw this.

To left and right the great corridor of the barracks stretched away, a channel of two-tier bunks, equipment lockers, and bio facilities. Below and above too, before and behind, through translucent walls and ceilings, you could see similar corridors arrayed in a neat rectangular lattice, fading to milky indistinctness. Everywhere, the ranks of bunks were emptying as the recruits filed out for the calisthenics routines that began each day. This entire moonlet, the Barracks Ball, was hollowed out and filled up with a million ensigns and other trainees, a million would-be pilots and navigators and engineers and ground crew, all close to Pirius’s age, all eager to be thrown into the endless fray.

Arches Base was primarily a training academy for flight crews. The cadets here were highly intelligent, physically fit, very lively — and intensely competitive, at work and off duty. And so the place was riven with factions which constantly split, merged and reformed, and with feuds and love affairs that could flare with equal vigor. Today it was Pirius’s bunk that Captain Seath was standing before, and from the corner of his eye Pirius could see that everybody was looking at him with unbridled glee. His life wasn’t going to be worth living after this.

Seath was walking away. “Pirius, put your pants on. A ship’s come in. You’ve got a visitor.”

“A visitor?… Sorry, sir. Can I ask what ship?”

Seath called over her shoulder, “The Assimilator’s Claw. And she’s been in a scrap.”

That was enough to tell Pirius who his visitor must be. Torec and Pirius stared at each other, bewildered.

Seath was already receding down the long corridor, here and there snapping out a command to an unfortunate ensign.

Pirius scrambled into his pants, jacket, and boots. He held a clean-cloth over his face, endured a second of stinging pain as the semisentient material cleaned out his pores and dissolved his stubble, and hurried after Seath. He was relieved to hear Torec hurrying along in his wake; he had a feeling he was going to need some familiar company today.

Pirius and Torec bundled after Captain Seath into a flitter. The little ship, not much more than a transparent cylinder, closed itself up and squirted away, out of the Barracks Ball and into space.

All around Pirius, worlds hailed like cannonballs.

The Barracks Ball was one of more than a hundred swarming worldlets that comprised the Arches Cluster base. Beyond the rocks, of course, hung the hundreds of giant young stars that comprised the cluster itself, tightly packed — in fact, the largest concentration of such stars in the Galaxy. Above the stars themselves was a still more remarkable sight. Glowing filaments, ionized gas dragged along the loops of the Galaxy’s magnetic field, combined into a wispy interstellar architecture constructed on a scale of light-years. The characteristic shape of these filaments had, it was said, given “Arches” its name.

The Galaxy center itself was just fifty light-years away.

It was a stunning, bewildering sky — but Pirius, Torec, and Seath had all grown up with it. They made no comment as the flitter laced its perilous route through the shifting three-dimensional geometry of the base.

Besides, Pirius had more on his mind than rocks and stars.

Torec looked composed. She was a little shorter than he was, a little broader at the shoulders. She had a thin face, but a full mouth, startling gray eyes, and brown hair she wore in rows of short spikes. Her nose was upturned, a feature she hated, but Pirius thought it made her beautiful. They had been each other’s squeezes, in barracks argot, for a couple of months now — staggering longevity in the fevered atmosphere of the barracks. But, despite the taunting from their colleagues, they showed no signs of falling out. Pirius was glad that Torec’s calm presence was with him as he faced the strangeness to come.

It was standard policy for any data FTL-leaked from possible futures to be presented immediately to any individual named in that data. Some of Pirius’s friends even knew when and how they were going to die. And so Pirius already knew, everybody knew, that in the future he was destined to pilot a ship called the Assimilator’s Claw. But the Claw hadn’t yet been commissioned. If a version of the Claw had come into dock — and a captain had taken the time to come get him from his bunk to meet a visitor — that visitor could only be one person, and his heart hammered.

The flitters destination was a dry dock. Perhaps a hundred kilometers across, this Rock was pocked by pits where ships nestled. They were all shapes and sizes, from one-person fighters smaller than greenships, through to ponderous, kilometer-wide Spline ships, the living vessels that had been the backbone of the human fleet for fifteen thousand years.

And in one such yard sat a single, battered greenship. It must be the Assimilator’s Claw, and as Pirius first glimpsed the scarred hull of his future command, his breath caught in his throat.

Torec nudged his elbow and pointed. A cluster of ships hovered maybe half a kilometer above the Ball’s surface in a cubical array, and Pirius saw the flicker of starbreaker beams and other weapons. Within the array he glimpsed a sleek shape, caged within that three-dimensional fence of fire, a shape with folded wings, black as night even in the glare of the cluster’s huge suns.

“Lethe,” he said. “That’s a Xeelee ship.”

“And that,” said Seath coldly, “is the least of your troubles.”