“The network will grow incrementally,” Shelley said. “We have to follow a phased approach, simply because it’s going to take time to ramp up the industrial capacity to churn out all those moles, all those condensers and collectors. And besides, nobody has ever run a pipe network on anything like this scale before. The moles will take some time to figure out the best way to do it.”

This was the modern approach to engineering. You let your machines, loaded with as much smartness as possible, figure things out for themselves, and then learn from the way they did it. That way, not only was there a good chance you’d end up with an optimal design at the finish, but you could expect that at every stage you would move from one optimum configuration to another. It was like climbing a hill, Shelley said, in such a way that you didn’t just aim for the peak but at every stage took the best path available.

“So in the end,” Tom said, “it will all merge together into a single vast cap of silicon brain embedded in the floor of the polar ocean. Talk about hubris!”

Ruud Makaay said ruefully, “Believe me, that word is already carved on my tombstone. All I can say is that we geoengineers would never take on a project like this if there was any choice.”

“But there is no choice,” Gea said in her small, absurd voice.

Tom said, “There’s still something I don’t get. I’m no engineer, but I do recall some high-school thermodynamics. You’re keeping those hydrate deposits cool; you’re pumping all the heat out with your liquid nitrogen. But where is all that heat going to? It can’t just disappear, can it?”

“It certainly can’t,” said Shelley.

Shelley patiently explained that our mechanism would end up dumping its heat into the ocean, and the air.

“This will be the hardest part of the sell, I fear,” Makaay said. “Because it is going to be very hard for our paymasters to understand.”

“Well, there’s no magic involved,” Shelley said. “All that heat has to go somewhere.” But the net injection of heat into the environment would be trivial compared to the catastrophic rise in temperature that would result if the hydrates’ vast store of greenhouse gases were released to do their worst. And anyhow we could always mitigate the effects of any heat injection with albedo control… It was a necessary evil, Shelley said.

Sonia said, “I don’t think I understand.”

Tom laughed. “They’re going to pump all that heat out of the hydrate layers and into the air. The whole point is to stop the world from heating up. But to do that we’re going to have to make the problem worse. What a joke.”

The Gea robot said, “There are many aspects of the present predicament of mankind that are ironic. It is indeed all a vast joke. Ha ha.” And she rolled back and forth, friction sparks cascading.

Alia, seeking a way forward, sought the Transcendence.

When she called, the strange constellation of minds gathered around her. To rejoin the Transcendence was easy, even here, on the hive-world. Once you had been a part of the Transcendence, you never really left it; it was always in the background of your life, always waiting to take you in once more.

It was exactly like an addiction, Alia thought uneasily.

But now she sensed a kind of restlessness. The Transcendence, aware of its own imperfections and incompleteness, struggled to be born — and laced through it all was that nagging guilt over the bloodiness of the past from which it was emerging.

She looked back at herself, Alia, her own nuggetlike awareness embedded in the greater whole. To be part of the Transcendence was to be overwhelmed by perspectives, human and superhuman, that overlapped and clashed. On one level she struggled to maintain her sense of identity and purpose, and to unravel her doubts about the Redemption — but at the same time she was faintly ashamed of herself. Who was she to question the mass mind around her, which had been gracious enough to accept her, and which was in turn founded on the wisdom of others far older and wiser than she was? Even now, unready as she felt, she could simply give herself up to the greater whole. She could put aside Alia, like a memory of childhood; she could immerse herself in the Transcendence, and never surface again…

Which was what it wanted, she realized. For her nagging questions, lodged deep within its own consciousness, made the Transcendence uncomfortable. She couldn’t take credit for causing this conflict within the Transcendence, but her questions were opening wounds, sharpening a conflict that already existed.

But she clung to herself, like a defiant child who wouldn’t say sorry. This was a genuine dilemma for the Transcendence, and she had a duty to keep asking her questions: What is the true purpose of the Redemption? What is its ultimate goal? What does it cost? And — how far will you take it?

The constellations of pinpoint minds seemed to swim around her — and then they came together with a shocking rush. She saw a human face, a small, round, worn face, with eyes like bits of diamond.

And she heard a voice, resounding inside her head. “You won’t give up, will you, child?”

“I only want—”

“What you want doesn’t matter. What the Transcendence wants is for your doubts to be replaced by certainty. For, you see, it seeks certainty itself. You know that the impulse for Redemption comes from the communities of the undying. And so you must meet the undying, the oldest of all. You must meet me. My name is Leropa. Find me.”

“Where?”

Suddenly Alia surfaced from the Transcendence.

She was back in her own body, back on Reath’s shuttle. She lay on a couch. Reath and Drea hovered over her, concerned. But the three Campocs had backed against a partition, huddled together like frightened children. It struck her that joining the Transcendence was like being ill.

And that strange face, Leropa’s face, hovered in the air before her. Alia cried out. It was as if she had woken, but her nightmare still haunted her.

It, she, Leropa, glanced dismissively at the Campocs. “They can hear me, with their little web of minds. I’m invisible to the others.”

Alia struggled to sit up. “Where must I go? Tell me.”

“Earth,” the woman said.

And then the face was gone — not broken up or dispersed, simply gone from Alia’s field of view, as if she had turned her head away.

Had any of it happened? Had this strange woman Leropa really come swimming out of the Transcendence to address her? Had she really talked of Earth?

The Campocs remained jammed up against each other, trembling, watching her fearfully, and Drea stared at her, baffled, concerned.

I spoke to Rosa again. She told me, “There has been an upsurge in sightings — hauntings, poltergeist phenomena, you name it — all over the planet.”

“Really? I had no idea.”

She snorted. “Why would you? You would not look in the places where you might discover such things. Nor would I, in normal times. But, prompted by your experiences, I have been researching. You aren’t alone, Michael, for better or worse. The whole world is suddenly haunted! And this has happened before. History shows it; there have been previous plagues of ghosts. Now, what do you suppose this means?”

I had no idea. I didn’t know whether to be reassured or terrified.

I felt guilty about working on this stuff in the middle of the hydrate project. I kept it a secret from Tom, Shelley, and the others. It was like I was looking at porn. But I did it. I summoned Rosa, like raising a VR ghost, to my Palm Springs hotel room.

In the flimsy gaudiness of the room, with its late-twentieth-century American tourist chic, Rosa was a dark, sullen mass, small and hunched, her priest’s robes so black they seemed to suck the light out of the air. When she first appeared she seemed disconcerted. She looked around as if finding it hard to focus. Then she saw me, and nodded, unsmiling. “Michael.”