The audience, stunned, fell silent. The only sound was a low, broken crying from the wreckage of the stage, and Rees watched, unbelieving, as a red-brown stain spread over the remains of the trampoline.

A burly man bearing orange braids hurried from the wings and stood commandingly before the audience. "Sit down," he ordered. "No one should try to leave." And he stood there as the audience quietly obeyed. Rees, looking around, saw more orange braids at the exits from the Theatre, still more working their way into the ruins of the stage.

Baert's face was pale. "Security," he whispered. "Report directly to the Captain. You don't see them around too often, but they're always there… undercover as often as not." He sat back and folded his arms. "What a mess. They'll interrogate us all before they let us out of here; it will take hours—"

"Baert, I don't understand any of this. What happened?"

Baert shrugged. "What do you think? A bomb, of course."

Rees felt an echo of the disorientation he had suffered when the drinks girl had walked by. "Someone did this deliberately?"

Baert looked at him sourly and did not reply.

"Why?"

"I don't know. I don't speak for those people." Baert rubbed the side of his nose. "But there's been a few of these attacks, directed against Officers, mostly, or places they're likely to be. Like this.

"Not everyone's happy here, you see, my friend," he went on. "A lot of people think the Officers get more than their share."

"So they're turning to actions like this?" Rees turned away. The red-stained trampoline was being wrapped around the limp bodies of the gravity dancers; he watched with an unshakeable sense of unreality. He remembered his own flash of resentment at Baert, not more than an hour before this disaster. Perhaps he could sympathize with the motives of the people behind this act — why should one group enjoy at leisure the fruits of another's labor? — but to kill for such a reason?

The orange-braided security men began to organize strip searches of the crowd. Resigned, not speaking, Rees and Baert sat back to wait their

turn.

Despite isolated incidents like the Theatre attack Rees found his new life fascinating and rewarding, and the shifts wore away unbelievably quickly. All too soon, it seemed, he had finished his Thousand Shifts, the first stage of his graduation process, and it was time for his achievement to be honored.

And so he found himself sitting on a decorated bus and studying the crimson braids of a Scientist (Third Class), freshly stitched to the shoulder of his coverall, and shivering with a sense of unreality. The bus worked its way through the suburbs of the Raft. Its dozen young occupants, Rees's fellow graduate-apprentices, spun out a cloud of laughter and talk.

Jaen was studying him with humorous concern, a slight crease over her broad nose; her hands rested in the lap of her dress uniform. "Something on your mind?"

He shrugged. "I'm fine. You know me. I'm the serious type."

"Damn right. Here." Jaen reached to the boy sitting on the far side from Rees and took a narrow-necked bottle. "Drink. You're graduating. This is your Thousandth Shift and you're entitled to enjoy it."

"Well, it isn't precisely. I was a slow starter, remember. For me it's more like a thousand and a quarter—"

"Oh, you boring bugger, drink some of this stuff before I kick you off the bus."

Rees, laughing, gave in and took a deep draught from the bottle.

He had sampled some tough liquors in the Quartermaster's bar, and plenty of them had been stronger than this fizzing wine-sim; but none of them had quite the same effect. Soon the globe lights lining the avenue of cables seemed to emit a more friendly light; Jaen's gravity pull mingling with his was a source of warmth and stillness; and the brittle conversation of his companions seemed to grow vivid and amusing.

His mood persisted as they emerged from beneath the canopy of flying trees and reached the shadow of the Platform. The great lip of metal jutted inwards from the Rim, forming a black rectangle cut out of the crimson of the sky, its supporting braces like gaunt limbs. The bus wheezed to a halt alongside a set of wide stairs. Rees, Jaen and the rest tumbled from the bus and clambered up the stairs to the Platform.

The Thousandth Shift party was already in full swing, bustling with perhaps a hundred graduates of the various Classes of the Raft. A bar set up on trestle tables was doing healthy business, and a discordant set of musicians was thumping out a rhythmic sound — there were even a few couples tentatively dancing, near the band's low stage. Rees, with Jaen in tolerant tow, set off on a tour of the walls of the Platform.

The Platform was an elegant idea: to fix a hundred-yard-square plate to the Rim at such an angle that it matched the local horizontal, surround it by a wall of glass, and so reveal a universe of spectacular views. At the inward edge was the Raft itself, tilted like some huge toy for Rees's inspection. As at the Theatre the sensation of being on a safe, flat surface gave the proximity of the vast slope a vertiginous thrill.

The space-facing edge of the platform was suspended over the Rim of the Raft, and a section of the floor was inset with sheets of glass. Rees stood over the depths of the Nebula; it felt as if he were floating in the air. He could see hundreds of stars scattered in a vast three-dimensional array, illuminating the air like mile-wide globe lamps; and at the center of the view, towards the hidden Core of the Nebula, the stars were crowded together, so that it was as if he were staring into a vast, star-walled shaft.

"Rees. I congratulate you." Rees turned. Hol-lerbach, gaunt, unsmiling and utterly out of place in all this gaiety, stood beside him.

"Thank you, sir."

The old Scientist leaned towards him conspirato-rially. "Of course, I didn't doubt you'd do well from the first."

Rees laughed. "I can tell you I doubted it sometimes."

"A Thousand Shifts, eh?" Hollerbach scratched his cheek. "Well, I've no doubt you'll go much further… And in the meantime here's something for you to think about, boy. The ancients, the first Crew, didn't measure time exclusively in shifts. We know this from their records. They used shifts, yes, but they had other units: a 'day,' which was about three shifts, and a 'year,' which was about a thousand shifts. How old are you now?"

"About seventeen thousand, I believe, sir."

"So you'd be about seventeen 'years' old, eh? Now then — what do you suppose these units, a 'day' and a 'year,' referred to?" But before Rees could answer Hollerbach raised his hand and walked off. "Baert! So they've let you get this far despite my efforts to the contrary—"

Bowls of sweetmeats had been set out around the walls. Jaen nibbled on some fluffy substance and tugged absently at his hand. "Come on. Isn't that enough sightseeing and science?"

Rees looked at her, the combination of wine-sim and stars leaving him quite dazed. "Hm? You know, Jaen, the stories of our home universe notwithstanding, sometimes this seems a very beautiful place." He grinned. "And you don't look too bad yourself."

She punched him in the solar plexus. "And nor do you. Now let's have a dance."

"What?" His euphoria evaporated. He looked past her shoulder at the whirl of dancing couples. "Look, Jaen, I've never danced in my life."

She clicked her tongue. "Don't be such a coward, you mine rat. Those people are just ex-apprentices like you and me, and I can tell you one thing for sure: they won't be watching you."

"Well…" he began, but it was too late; with a determined grip on his forearm she led him to the center of the Platform.

His head filled with memories of the unfortunate gravity dancers at the Theatre of Light and their swooping, spectacular ballet. If he lived for fifty thousand shifts he would never be able to match such grace.