Matthew nodded slowly. “I see,” he said. “So evolution happens as organisms change. Natural selection without genetic load. Metamorphosis instead of death.”

“Emortality’s not immortality,” Lynn reminded him. “Things die here. There’s eating—herbivorous andcarnivorous. There’s predation and parasitism. Lots of death—but the organisms that don’t die may not be existentially stuck the way we are. They may be able to go on renewing themselves and changing themselves indefinitely—although it’ll take a long time to prove it.”

“Maybe Vince’s werewolves weren’t such a silly idea after all,” Matthew said. “Maybe you can sell him on the idea that it was a werewolf-analogue that killed Bernal. Not exactly a healthy scenario for a first contact, though, is it? I see what you mean about the bad alternative and the worse one. I can see why you didn’t want to address the question, and don’t want Vince to address it either.”

“That’s not fair, Matthew,” the bald woman said, defensively. “It’s the worldthat’s the important puzzle. That’s the mystery we need to solve—because that’s the mystery that could be the death of every last one of us, if we don’t solve it.”

“I know that,” Matthew assured her. “So let’s get on with the grand tour, shall we?”

TWENTY

While waiting to shuttle down, Matthew had studied most of the available film of the ruined city, using the VE-hood above his bed to take a virtual tour along the same route that Lynn Gwyer was following, so he was now beset by an eerie feeling that he was acting out a half-forgotten dream. He’d had similar experiences back on Earth, when he’d visited established tourist attractions in VE in order to work out exactly what he wanted to see when he got to the real thing. He was already familiar with the ways in which real tours expanded the horizons of virtual ones, offering a better appreciation of size and context.

The film clips had, of course, concentrated on those parts of the city that had been partially cleared of the enshrouding vegetation. It was not until he saw the remainder in all its glory that Matthew realized why the flying eyes entrusted with the work of mapping and surveying the new world had not been able to pick it out for more than a year. So completely were the stone walls overgrown, overlaid, and obscured that it had taken a revelatory freak of chance to provide the first evidence of artifice.

Matthew soon came to understand, as Lynn led him over the ridge separating the Base Three bubbles from the nearest wall of the city, that even after a further year-and-a-half of searching, there might easily be other structures of a similar kind as yet undiscovered.

“Your methods of clearance seem to have been rather brutal,” Matthew commented, as he followed the makeshift path.

“There were only four of us at first,” Lynn reminded him. “We would have liked more reinforcements, but Milyukov wouldn’t send them. He blamed the trouble aboard the ship, but I think he was afraid we’d find what we were looking for. If we do find intelligent aliens, Tang’s case will look a lot stronger. Milyukov wants to delay any discovery until he’s settled his domestic difficulties, and he’s campaigning hard for the conference at Base One to come up with a vote in favor of staying put. So we didn’t really have much choice. We moved on from machetes to chain saws in a matter of days, then figured we might as well go the whole hog and started blasting away with flamethrowers. If we’d had any authentic archaeologists to help us out they’d have fainted with horror, but Dulcie’s not that delicate.

“When we get up to the top you’ll be able to see the outlines of the lesser walls, but you won’t be able to make out their true extent and shape. Even with flamethrowers we haven’t been able to clear more than a tiny fraction of the whole array. The distinction between changes in the contours of the hills and the artificial constructs is hard to see, even with a practiced eye.”

As they toiled up the slope, following a pathway that was far from straight, Matthew’s limbs soon began to ache with the effort. It seemed that every time he came close to a crucial adjustment to circumstance he immediately began to put a renewed strain on his long-frozen muscles. Lynn was moving slowly, continually pausing to lend him a helping hand whenever he allowed his unsteadiness to show, but he knew that he had to make his own way.

At least the stress of climbing distracted him from the ever-present unease caused by the fact that his reflexes were slightly out of tune with the gravity-regime. That would doubtless surface again when he got down to lab work, or when someone pressed him into an educative ballgame.

Further distraction was provided by an increasingly keen awareness of the inadequacy of his eyes. As Lynn had warned, it was easy enough to see where human hands had been at work peeling vegetation away from the walls and burning back the debris, but where there had been no obvious interference it was very difficult to see the evidence of nonhuman work beneath the camouflage of nature.

Wherever patches of stonework had actually been cleared their artificial nature was starkly obvious, but where the purple plants still overlay them the alienness of the life-forms confused all earthly expectations. There were organisms analogous to lichens, to fungi, to mosses, and to creepers, as well as the curious dendrites, but all the appearances were deceptive and that deceptiveness swallowed up every sign that humanlike hands had ever been at work.

As they climbed higher more territory became visible, at least periodically, but the panorama remained utterly confusing to the naked eye, at least until Matthew glimpsed something that stuck out like the proverbial sore thumb.

“What’s that!” he demanded, pointing.

Lynn chuckled. “That’s ours,” she said. “It’s the cabin of Bernal’s boat. The lake and the river are still mostly obscured, but you’ll be able to see the lake and the lower part of the watercourse from the tower.”

“Whose idea was it to paint the damn thing pea green?” Matthew demanded. “I never thought of Bernal as an Edward Lear fan.”

“It won’t be going all the way to the sea,” she reminded him, to indicate that she understood the reference, “and it certainly won’t be manned by an owl and a pussycat, no matter who gets the final berth. It isn’t painted—that’s chlorophyll, to feed the biomotor.”

“It’s powered by a biomotor? Not built for speed, then.”

“It has a conventional engine too, but there’s a fuel problem. Bernal figured that we wouldn’t really need the inorganic engine till the return journey, when we’ll be coming upstream. We wouldn’t actually have to carry a huge stock of fuel, given that we’ve got converters that can process local vegetation into a usable alcohol mix, but gathering material to feed the converter takes a lot of work and the converter uses up fuel at a fair rate itself. Given that we needed to equip the boat with certain other bioanalogous features, and the desirability of a fail-safe backup, Bernal decided that it would be best to double up. He was careful to point out that it’s in keeping with local traditions too.”

Matthew was quick to pick up on that point. “Bernal was trying to figure out the logic of nutritional versatility—the lack of distinction between fixers and eaters. So he wanted to use the boat to … to what, exactly? To make a point? To explore a hypothesis?”

“His argument was that if so many of the local invertebrates can function as plants or as animals, there must be a reward for versatility. Given that the world itself isn’t very active, and the weather patterns are so benign, he figured that it couldn’t be a response to the inorganic frame. He’d have liked to build a link to the gradual chimerical renewal business, but he couldn’t swallow the notion that emortal animals might be routinely capable of turning into emortal trees—and even if they were, he couldn’t see any reason why the homeobox shouldn’t make chloroplast-analogues for plant forms and get rid of them completely in animal forms. So he—that is, we—figured it had to be something to do with the way the organisms interact with one another. There must be ecosystemic factors of some kind that determine the usefulness of switching back and forth between modes of nourishment on an ad hoc basis: something analogous, however esoterically, to a boat whose energy-requirements change abruptly whenever it switches from going downstream to going upstream. It’s not exactly making a point or exploring a hypothesis … more a sort of heuristic device: an aid to inspiration.”