Ve turned to Orlando. "I don't think they're in hiding. How shy could they be, after giving the atmosphere a spectrum that screams, 'Civilization! Come and visit!' We only noticed it close up, but it wouldn't take a huge technological advance to spot it from thousands of light years away.

Orlando didn't reply; he'd been staring down into the puddle, and he continued to watch a swarm of crimson larvae molting, and eating each other's discarded skins. Yatima understood the stake he had in making contact with the Transmuters. By the end of the Diaspora, when his scattered clones had reconverged, the Earth would be habitable again—but he could never feel secure about returning to the flesh until Lacerta had been explained. Any Coalition theory was likely to remain as suspect as the original belief that Lac G-1's neutron stars would take seven million years to collide. But if the Transmuters had firsthand knowledge of the galaxy's dynamics on a timescale of millions of years—and were beneficent enough to transform this planet's atmosphere, atom by atom, just to save their distant relatives from extinction—surely they wouldn't begrudge an infant civilization a little information and advice on its own long-term survival.

"Okay." Orlando looked up. "Maybe the spectrum was meant to stand out like a beacon. Maybe that's the whole point. They could have preserved the atmosphere in a thousand other ways, but they chose a method that would get them noticed."

"You mean they went out of their way to attract attention? Why?"

"To bring people here."

"Then why are they being so unsociable? Or are they just waiting to ambush us?"

"Very funny." Orlando met vis gaze. "You're right, though: they're not hiding from us, that's absurd. They're gone. But they must have left something behind. Something they wanted us to see."

Yatima gestured at the oasis.

Orlando laughed. "You think they built this as an ornamental pond, and invited the whole galaxy to come and admire it?"

"It doesn't look like much now," Yatima admitted. "But even loaded with deuterium and oxygen-18 it's been drying out slowly. Six billion years ago it might have been spectacular."

Orlando was not persuaded. "Maybe we're both wrong about the biosphere. Maybe there was no life here at all when the Transmuters left; it could have evolved later. The persistence of water vapor might he nothing but a side effect of the method they chose to make Swift stand out to anyone with a decent spectroscope and a glimmering of intelligence."

"And we just haven't searched hard enough for whatever it is we were meant to find? The lure wasn't exactly subtle, so the payoff should be just as hard to miss. Either it's turned to dust, or we're looking at the dregs of it right now."

Orlando was silent for a moment, then he said bitterly, "Then they should have used a beacon that turned to dust, too."

Yatima resisted pointing out the technical problems with choosing isotopes with suitable half-lives. Ve said, "They might have visited other planets, and left something more enduring. The next C-Z to arrive might find some kind of artifact…" Ve trailed off, distracted. Another possibility was hovering on the edge of consciousness; ve waited a few tau, but it wouldn't break through. Keeping vis icon in the Swift scape—along with vis linear input, in case Orlando spoke—ve shifted vis gestalt viewpoint to a map of vis own mind.

The scape portrayed a vast, three-dimensional network of interlinked neuron-like objects, but they were symbols, not junctions in the lowest-level network that dealt with individual pulses of data. Each symbol glowed with an intensity proportional to the reinforcement it was receiving from the others already dominating the network: vis conscious preoccupations. Simple linear cascades were rapidly tried out, then inhibited as stale or vis mind would have been paralyzed by positive feedback loops of hot/cold, wet/dry banality—but novel combinations of symbols were firing all the time, and if they resonated strongly enough with the current activity, their alliance could be reinforced, and even rise to consciousness. Thought was a lot like biochemistry; there were millions of random collisions going on all the time, but it was the need to form a product with the right shape to adhere firmly to an existing template that advanced the process in a coherent way.

The map was a slow-notion replay; Yatima was looking at the firing patterns behind the nagging sensation that hadn't quite gelled, not the real-time firing caused by the act of looking at the map. And, color-coded by the map's software, the relevant alliance was easy to pick out, though by chance it hadn't quite crossed the threshold into self-supporting activity. Symbols had fired for isotope, enduring, obvious… and neutron.

Yatima was baffled for a moment, then the sense of connections falling into place welled up again, and ve knew exactly what ve hadn't quite thought before. If the heavy, but stable, isotopes in Swift's atmosphere were meant to attract attention to something enduring, what could be more enduring than the atoms themselves? The isotopes weren't a message from the Transmuters saying, "Come and search this world for our libraries full of hard-won knowledge… even though they might have turned to dust" or "Come and marvel at this life we created… even though it might have gone extinct."

The isotopes were saying, "Come and look at these isotopes."

Orlando screamed, "You idiot! What are you doing?"

Yatima jumped back fully to the Swift scape. Vis car was shown half submerged in the oasis—and it was clear that either the probe itself or its gas jets had punctured the membrane. As the car ascended, the exposed water erupted into bubbles tens of delta wide, which burst into clouds of rapidly dissipated steam. Even as the surface boiled, the torn edges of the membrane sent sticky tendrils flying across the gap, and a few of these threads met and merged, crisscrossing the wound with a loose gauze to act as an anchor for repolymerization. But the hole was too large, and the rush of steam and the churning of the water shredded the tenuous scaffolding. The membrane ruptured further. The process was unstoppable now.

Orlando was standing on the seat of his car, shouting and gesticulating. "You idiot! You've killed them! You fucking idiot!" Yatima hesitated, then jumped Konishi-style straight into the car and seized him by the shoulders.

"It's all right! Orlando, they'll survive! They're adapted for it!" He pushed ver away, flailing his arms, bellowing with grief and rage. Yatima didn't try to touch him again, but ve kept his eyes on him, and repeated calmly, "They'll survive." That wasn't entirely true; only about one in three individual creatures made it through boiling and rehydration.

Ve glanced down; the whole oasis was little more than a patch of mud now, a sticky residue holding on to a few polymer-coated bubbles of steam, expanding slowly toward breaking point. All the colors of Swift life had merged into a faintly iridescent brown, without so much as an outline of any recognizable body plan. The solid geometry of the functioning organisms had been compressed into a mixture of two-dimensional proximity and chemical markers, but the process wasn't always reversible, nor was the coding entirely unambiguous. Even members of different species caught in a dry-out together sometimes rehydrated as mutual genetic chimeras, co-opting spores from each other to serve as tissues in their reconstituted bodies.

"Where were you?" Orlando's face radiated horror and contempt. "Those were real, living creatures—and you couldn't even keep your eyes on them!"

"There must have been a sudden downdraft. The autopilot would have kept the probe out of the water if there'd been any way of doing that."

"You shouldn't have been so low to start with!"