"This discovery finally explained to us why toolmaking species are rare to begin with. It takes an unusual combination of factors to create a species that is fit enough to survive, but at the same time is so unfit in its native environment that it must turn to its weakest organ, its brain, for help. Reliance on tools is a tremendous handicap for any species; only a few manage to turn it into an asset.

"The builders of Dis knew they were doomed. We all are: technological civilization represents a species' desperate attempt to build a bubble to keep hostile environments at bay. Sentient species also never cooperate with one another over the long term, because the environments they need in order to live are incompatible. Some, like the Chicxulub, accept this easily and try to exterminate everyone else. Even they can't stop their own evolution and so eventually they cease to be starfaring species. Destruction or devolution are the only choices.

"It's hard to see how we can cohabit with the autotrophs and the sylphs, if humanity is bent on expansion and so are they. Something catastrophic is bound to happen; and if not, well, we'll just evolve away from what we are, sooner or later."

"That's about as bleak a story as you can get," said Rue. She scowled off into space for a while. "But you still haven't answered my question: how is Jentry's Envy different?"

Herat nodded. "Two things. One is something we found on Dis, something that scares me even to think about. But I'll start with the other, obvious one: Jentry's Envy appears to have been built for more than one kind of species to use— not just more than one species, more than one kind. It implies the one thing we've never seen: multispecies cooperation. If it's not a fluke, a one-time happening in the history of the galaxy, then it suggests there may be a way to break the cycle of competition and destruction that's ruled since the first stars were born.

"But the other thing, the thing that scares me right now, is that while we were on Dis we found evidence that a number of other races had visited Dis in the past— searchers, like ourselves. In two places, we even found Lasa graffiti."

"Graffiti?"

"Well… artifacts and writings, like the ones on the habitat here. We haven't fully translated it, but the point is that one of those pieces of writing dates to the Lasa period, two billion years ago. We know it's Lasa because it illuminates the meaning of other samples we have— it's either Lasa or somebody who could think in the language. But the other…

"The other thing was a piece of Lasa technology that also appears genuine, because its integrated data storage has the unforgeable mathematical signature of the Lasa," said Herat. "But when we dated it, we found it to be only twenty thousand years old."

Salas whistled and sat back. "Two billion years…"

Herat shook his head. "It's impossible. But every time I see the pictures of that habitat out there, with the Lasa writing on it, I wonder… Were the poor inhabitants of Dis right— is a permanent civilization possible? If so, how? What's frightening is the thought of how you might have to live— how you'd have to understand the world— in order to maintain a civilization for two billion years."

"Y OU'RE SET TO go, people," said Rue Cassels. She waved down at Michael. "All signs looking good."

They were not wasting time. Michael had only just had breakfast and now he found himself clutching the lip of Lake Flaccid's shore, preparing to dive into who knew what. It was probably better to do it this way. Otherwise he might have to think about where he was about to go and that would be bad.

Michael heard Herat sigh. "Okay, let's do it." Michael let go of the shore of Lake Flaccid and let himself sink.

Real vision was impossible here. As the surface of the lake closed over the top of his helmet, Michael had a startling moment of déjà vu: He remembered as a child standing on the edge of a cliff in wintertime. He was all bundled up in a parka with the hood up and had been gazing out at some mountain sheep on a far slope, when a snow squall came up. In seconds everything went blank and he couldn't see more than a meter beyond his feet. Terrified, he had stood there for half an hour, englobed in white, until the storm abated and he could once again see the sheer drop at his feet. He had never gone to stand on that particular spot again.

The evac suit felt much like a parka and as soon as he entered the lake he was embedded in milky whiteness. For a while he just stared at it, able to see swirls and layers in it as he descended. He waved his arms experimentally. It certainly felt like he was underwater.

Then Dr. Herat's voice broke him out of the reverie: "Look at it! It's magnificent!"

Michael switched to the inscape view provided by the mesobot "fish." The sonar mappings of all three fish were combined into one 3-D model and Michael's POV was adjusted to match his actual position in that model. He could look around and it was almost as if it were his own eyes that saw, in false color, the interior of the alien habitat.

The first thing he noticed was that the wall he was following down did not extend all the way to the bottom of the habitat. There were windows just below him, then under that great arches opened up. The material of the walls swept down to become pillars that grounded in a blurry maze at the bottom; of course, since the habitat was a rotating sphere, the arches looked more like the arms of a star radiating out from the cylinder at the axis.

There were numerous round «signs» like those they'd found above, set in vertical rows in the wall. When the sonar hit them just right, they turned into complex three-dimensional swirls that seemed to move. Beautiful.

"It's all open down here." Herat was enjoying this altogether too much. In some ways, the man had no imagination, Michael had decided; he couldn't picture the nightmares that most people glimpsed in shadows. To him, this was just another place. True, Herat knew the utility of imagination; that was why he had hired Michael.

Their lines could snap (though they were fullerene, strong enough to suspend a whole building) and they might fall into jagged wreckage or even traps down in that blurred substrate. Or the weird aerogel beads could penetrate the suit somehow.

Or there might just be live things in here after all…

"How are you guys doing?" asked Rue. The marine answered, "Great, thanks," with more than a tinge of relief in his voice. "I'm good, Rue," said Michael.

Experimentally, he switched off the inscape view. It was dark down here now— an unremitting slate gray, not at all like water. He held up his hand and couldn't see it until he plastered his palm against the faceplate.

"Tell me again what you're looking for?" asked the marine.

"Evidence of habitation," said Herat. "That means organic materials, ad-hoc structures— bodies would be ideal. We want to know whether this cycler was launched with a crew who later abandoned it or died here. Why is it empty? That's what I want to know right now."

"Yes, sir. My instructions are not to allow you to enter any small spaces, sir."

Michael flipped back to inscape. Dr. Herat's fuzzy outline was floating near one of the «window» openings. It wasn't dark in there— sonar shadows in this view were like solid extensions of the objects casting the shadow. Every now and then the triangulation of the three mesobots failed and one of the space-suited figures would grow a long spike-shaped tail for a few seconds.

"Bring one of the bots down here," commanded Herat. Something small and sleek slid up through the water to him, and the archway below Michael's feet vanished. He saw his own feet grow long pillars that grew down into indeterminacy.