"Is that an original?" Auger asked.

"No-it's a facsimile based on the surface scan of the original made by Ca.s.sandra," Tunguska said.

"But it should be accurate enough for our needs, if there's genuinely latent information buried on it."

"Take my word for it," Floyd said, "either that music-killing virus has already found its way into my

head or there's something wrong with that recording."

"There could be a high-frequency signal encoded in the groove," Tunguska said. "Enough to hold a significant chunk of that antenna data. I can verify this very quickly-"

"How quickly?" Auger asked, her impatience getting the better of her.

He blinked. "That quickly. It was just a question of examining Ca.s.sandra's holographic data and looking

for something anomalous in the structure. It's always much easier to identify a pattern if you have some idea of what you're looking for."

"And?" she persisted, barely able to keep still in her seat.

"Floyd is correct. There is an additional channel of information imprinted on to this recording. Not

enough to render the original music unbearable, but enough to upset someone with Floyd's refined tastes." He awarded Floyd a gentle, rather admiring smile. "We'd never have noticed it otherwise." Tunguska turned the platter this way and that, admiring the play of light across its reflective black surface. "A thing of beauty, really. But also something of a double-edged sword."

"We helped them," Auger said. "We got that information out of Paris, thinking we were saving priceless artefacts."

"They must have known all about your efforts to smuggle cultural data out of the city," Tunguska said. "Given that Niagara's agents needed to smuggle their own data out at the same time, your operation suited their purposes perfectly. All they had to do was bury the information in those recordings and make sure they fell into Susan's hands. Flooding the market with fakes was by far the simplest option."

"You know what?" Floyd said. "I wouldn't be too surprised if the Paris sphere was in that same warehouse complex. Even if Maillol had found it, he wouldn't have had any idea of its significance."

"They tricked us," Auger said, outraged and embarra.s.sed at the same time.

"You mustn't blame yourself," Tunguska said sternly. "Thanks to Susan's efforts, a vast amount of priceless material was saved from Paris. It's neither your fault nor hers that some of those artefacts were deliberately tainted."

"But that one disc can't possibly hold all the information," Auger said. "We have a box full of records," Tunguska said. He blinked again: some part of his mind whisking away to sift through Ca.s.sandra's data and her report on it. "It appears that a third of them have a similar microscopic structure. The rest, presumably, are genuine recordings."

"But we've been extracting records ever since we opened the Phobos portal," Auger said. "That's hundreds of thousands of recordings."

"It may not matter," Tunguska said. "You'll remember that Niagara was extremely keen to get his hands on the final shipment. It could be that the earlier shipments contained data that was in some way provisional or flawed. They may only just have got their antenna into a properly functioning state. Allowing time to combine the data strands from all three spheres...and to imprint the signals on to these recordings...and to distribute the recordings in such a way that they would fall plausibly into your hands...well, I have no difficulty believing that the final cargo was the most significant."

"Then we have a chance," Auger said. "If you can decode that embedded signal, of course."

"I don't antic.i.p.ate huge difficulties," Tunguska said. "Remember, it would have taken significant computing power to effect a complex encryption, which would have been as problematic for them as interpreting the data on E2 in the first place. I don't believe the encoding will tax us."

"I hope you're right."

"I'm already merging and processing the data," he said. "I've a.s.signed a significant portion of my ship's computing resources to the effort. Of course, we could still be chasing shadows-"

"We're not," Floyd said firmly.

With a certain reverence, Tunguska slipped the Louis Armstrong record back into its sleeve. "We're nearly ready for full bleed-drive thrust. We'll continue on our present heading, taking the most likely portal. Once in transit, we'll have eight hours to crack the numbers and determine the position of the ALS. It will be difficult-it may even be impossible-but at least it gives us the hope of one more lead against Niagara."

"You have your uses after all, Floyd," Auger said.

"Don't thank me," Floyd said. "Thank the music. I always said it would save the world."

THIRTY-NINE.

It was a little-travelled arm of the hyperweb, one that had seen only sporadic traffic since the Slashers had begun to map the network's further fringes. Five portals lay close together in a loose, drifting quincunx, separated by no more than a light-second of interstellar s.p.a.ce. There were no suns here, no worlds, no rogue moons-not even the rocky fragments of them, unborn or shattered. Only the spired husks of five large comets, dry and dead for billions of years, each of which formed an anchor for a single unmanned portal.

But there was something else. Sensors groped for it in the darkness. It was unthinkably dark, illuminated only by starlight. It was also unthinkably huge: as wide across as the sun itself, with room to spare.

"Are we too late?" Auger said as Tunguska a.s.sembled a composite picture of the ALS on one of the walls.

"I don't know. If my timing's correct, Niagara should only have achieved portal egress...ninety minutes ago."

"Then why don't we see him?"

"There's a faint thrust trail," Tunguska said. "It suggests that Niagara's already pa.s.sed around the limb of the ALS. Again-a.s.suming that the usual margins were ignored-he would have had just enough time to do that."

"So follow him."

"We are. Unfortunately, the bleed-drive needs further attention. This is the maximum acceleration we can sustain."

The composite image of the ALS gained detail by the second, as Tunguska's sensors teased more structure out of the darkness. Complex statistical methods squeezed the maximum information from meagre data. Auger recalled the briefing she had been given aboard the Twentieth Century Limited. Peter's schematic representation had been tinted a dull blue-grey, but there was not enough light here to trigger the eye's colour receptors. Tunguska's schematic ignored the faint ambient illumination and painted the entire structure a flat grey, with no shadowing except that necessary to suggest the platelike surface texturing. In Peter's overview, that platelike structure had made her think of something viral or crystalline, but now the hide of the ALS reminded her of some magnified view of human or animal skin, with a rough hint of irregularity and-here and there-signs where healing processes had not quite erased the evidence of former injuries. It was as if the ALS had been grown, rather than constructed.

Perhaps it had. No one had the slightest idea where the raw materials had come from. Maybe there had once been an entire solar system in this pocket of s.p.a.ce, which had then been efficiently strip-mined to create the hard, thin sh.e.l.l of the sphere. Or perhaps the necessary ma.s.s-energy had been conjured out of nothing, in some vastly more sophisticated version of the principle that underpinned the bleed-drive.

Auger looked at Floyd, wondering how he was taking all of this. "Not many people get to see this," she said. "If that's any consolation."

"I could have lived without it," he said. "Somehow I rather liked the idea that I could trust the night sky, or that the Sun was real."

"Your world is real, Floyd, and so are you. Nothing else matters."

"I'm picking something up," Tunguska said with quiet urgency. "It could be Niagara."

"An echo from his ship?" Auger asked.

"Not close enough for that," he said, "but there's a moving patch of enhanced brightness on the skin of the ALS. It's probably the reflection from his drive. He's doing his best to hide it, but there's only so much he can do if he still wants to steer."

"Remind me: do we have any more missiles in this thing?" Auger asked.

"None. I've instructed the factories to make more, but I can't afford to divert too much repair capacity away from the bleed-drive. I think we'll have to rely on beams, at least until later."

"Are we in firing range?"

"Not yet. We'll have to close quite a bit of distance for that."

"Can we get close enough?" Auger asked.

"Not if Niagara maintains his latest heading. But that reflection signature suggests that he's slowing

down, relative to the ALS."

"Why would he do that?" asked Floyd.

"Probably because he's ready to deploy the Molotov device," Tunguska said.

"You have to hit him before he has a chance."

"Are you sure you want that, Floyd? If that antimatter bomb doesn't blow a hole in the ALS, you won't

be going home."

"Just do it," Floyd said. "Worry about my return ticket later. A few hours ago I wasn't even expecting to live this long." "I don't think any of us were," Tunguska replied. His forehead creased, revealing some glint of interest in the storm of numbers flooding his head. "Ah. Now this may be significant." He looked around at their expectant faces. "I have some refined data on that reflection pattern. It looks as if there are two sources of light, rather than one."

Auger wondered if she understood him. "Two thrust beams?"

"Yes-but far enough apart that they can't be a.s.sociated with the same craft. It looks as if Niagara's

deployed a smaller ship from the larger one. We should have a hard echo any moment now..." He pressed a thick finger against one side of his temple.

"That makes sense," Auger said. "His main ship is just large enough to carry the Molotov device, right?"

"So it would seem."

"He's probably going to plough it into the ALS like a battering ram. Too much trouble to extract the

antimatter core, when he already has a ready-made delivery system." She pushed forward in her seat, ignoring the tension in her back. "The other ship must be a shuttle, something with enough range to make it to E2."

"That would be the ship carrying Silver Rain," Tunguska said.

"And Niagara," Auger added.

Tunguska shut his eyes, blanking out the extraneous distraction of the real world. "I see the shuttle, and the mother ship," he said. "The shuttle is on a high-gee burn trajectory away from the Molotov section." "Looks like it's trying to put as much distance between itself and the blast point as possible," Auger speculated.

Tunguska nodded, his eyes still closed.

"Well, you would, wouldn't you?" Floyd commented.

"Any chance of a beam strike any time soon?" she asked.

"Not yet. Believe me, my trigger finger is itching."

There was nothing to do but wait for the distance to be closed. Tunguska's long-range view gradually

sharpened, confirming that the two ships had indeed separated, and that the heavier of the two-the main craft, the one that they had been following from Earth-was racing on an accelerating trajectory towards the surface of the ALS, gunning its bleed-drive to the wall. The excess radiation from the tortured drive made it an easy object to track, even across such a distance. An hour earlier it had been moving parallel to the surface of the sphere, but now it was daggering down on a course that would intersect the surface at a right angle.

"We can't stop this, can we?" Auger said, exasperated. "That d.a.m.ned thing is going to hit the ALS no matter what we do."

"But admit it," Tunguska said, with more playfulness than she cared for. "Aren't you just a little bit curious to see what will happen?"

"I could stand not knowing," she said.

Tunguska opened his eyes. "Report from the bleed-drive: we're ready to increase our thrust to five gees.

Can't risk anything higher than that, for now at least. We won't need the acceleration caskets, although the ship will still have to immobilise us."

"Whatever it takes," Auger said.

The room quivered and swallowed them.

In the soft grip of the ship's protective systems, time surged and dragged in unpredictable, dreamlike