The next ecosystem was Fynbos, the characteristic environment of the Cape of Good Hope, cooler but no less sunny, a riot of scrappy flowering plants, a favorite of picnickers and birdwatchers from elsewhere in the Great Chain. It was a little too crowded for her taste, and so she marched straight down its length, trying not to be distracted by its many small charms, and entered the next block. This was almost more aquarium than terrarium, being a simulation of Old Earth Louisiana bayou. A plank walkway snaked among its moss-covered trees, carrying her over teeming reptile-infested waters to the airlock at its far end, where she stopped to pull a jacket out of her knapsack and don a pair of gloves.

Eight-hundred-year-old Douglas firs filled the next block from end to end. This one had been engineered to simulate the temperate rain forest of pre-Zero British Columbia, so its roof had been equipped with filters that damped the sun down to a steady silver glow that seemed to come from all directions. The lack of shadows made it seem brighter, in its way, than the unobstructed sunlight in the Chihuahuan biome. Ferns, moss, and epiphytes grew on fallen logs so thickly that they seemed to have been sprayed from a hose. A skein of faint paths ran through it. Kath Two followed one of them to the Kupol Grove: a relatively open space near the center, ringed by particularly enormous trees, where she found Doc, four of his students, his aide, and his robot sitting on moss-covered rocks and logs.

Dr. Hu Noah and most of his students were Ivyn. In Doc’s case it was difficult to tell, since extreme old age tended to obscure racial differences. He’d lost his hair long ago, and his skin was blotchy from years spent down on the surface doing research in unfiltered sunlight. Limp skin dangled from his sharp cheekbones like wet laundry from the edge of a rock, and eventually joined into a system of wattles mostly concealed by a scarf wrapped around his neck. That, and other touches meant to keep him comfortable, had been seen to by his nurse, a stocky Camite wearing a knapsack full of medical supplies. Curled at Doc’s feet like a sleeping dog was a grabb with a display panel in its back showing live readouts of his vital signs, which it was monitoring through a bundle of wireless connections. A pole projected vertically from its back to about the level of Doc’s waist, where it forked to a pair of handlebars. It was a smart cane. When he grabbed the handlebars it would help him stand up. It would then steady his locomotion even on the roughest terrain, adding its six legs to his two.

Doc’s students ranged in age from twenty to seventy. Kath Two had never met any of them before. There was nothing unusual in that; the TerReForm was the largest project ever undertaken by the human race, and 99 percent of it still lay in the future. She recognized the oldest one’s face from pictures in scientific journals.

She felt awkward. Walking into the clearing and making herself known to these people had required a kind of courage. There was a class system within TerReForm. Doc was at its apex. Survey personnel were not so much at its bottom as on its wild fringes. Not so much looked down upon as looked at askance, seen as not entirely serious.

But they were polite. All except Doc greeted her with the Ivyn variant of the salute, an understated gesture that incorporated a suggestion of a bow. Doc held both of his hands out so that she could take them carefully in hers. He squeezed with surprising strength and she squeezed back.

Then suddenly they were alone. Whether by prearrangement or because the other Ivyns had sensed something, they all withdrew. Even the nurse stepped away and contented herself with a stroll around the clearing, holding her hand up from time to time to check Doc’s readouts on a palm-sized device.

“You’re coming to Cradle with me,” he announced. “There is need of a team.”

“A new research project?” she asked.

Doc’s eyes closed for a moment in disagreement, then sprang open, gazing at her directly. “A Seven,” he corrected himself.

“Hmm. And I’m to be—”

“One of us, yes.”

Doc said this as if it were obvious. But it wasn’t, not to Kath Two. A Seven—a group consisting of one person from each race—was usually assembled for some ceremonial purpose, like dedicating a new habitat or signing a treaty. Not Kath Two’s thing at all. And even if it had been, she was confused by the suggestion that she was to be in the same Seven as Doc. Because usually, when a Seven was being assembled, some effort was made to have all the members be of like status. And this was decidedly not the case between her and Doc. The gap in age, fame, and eminence was almost too wide to measure.

What could possibly make Kath Two special enough to deserve such an honor?

Her confusion lasted for only a few moments before she saw it, so obvious: it was something to do with what she had seen on the surface.

She saw faint amusement around Doc’s eyes as he watched her figuring it all out. This turned to a mildly apprehensive look as he perceived that Kath Two was getting ready to blurt something. And that alone caused her to stifle it. She said nothing. They would talk of it only when Doc felt it was time.

“You’ve never been to Cradle before,” he said.

“That’s correct.”

“Well, it should be a new kind of adventure for you then.”

“I’ll try not to look like a tourist.”

“Look like whatever you please,” he said. “We’ll be too busy to worry much about such things.”

“When do we—”

“Twelve hours, give or take,” he said, and looked over to the Camite. “Is that about right, Memmie?”

Memmie nodded. “Cabins have been booked on the elevator departing at twenty-two thirty.”

Kath Two hadn’t met Memmie before, but had heard about this person of indeterminate gender who kept Doc alive and looked after many of his affairs. “Memmie” was short for Remembrance, a common Camite name. At the moment Memmie seemed to be presenting as female, with a saronglike wrap around the waist of a coverall that was otherwise utilitarian in the extreme, appearing to consist entirely of cargo pockets. Some neck jewelry and a turbanlike head covering completed the ensemble. Her use of the passive voice—“Cabins have been booked”—was racially typical. Memmie, of course, had done the booking, made the other arrangements, and looked after the significant fund transfers needed to book a number of elevator cabins on short notice. But getting her to say that this had been her doing would have been like extracting teeth from her jaw. Some saw it as a becoming habit of humility; others saw it as irritatingly passive-aggressive. Kath Two had no opinion. She had a few free hours on the Great Chain and needed to make the most of them.

“See you there,” she said.

“I shall look forward to it,” Doc answered.

KATH TWO DESCENDED TO THE TRANSIT LEVEL AT THE END OF THE block and took the tube around the ring to a district of midrise blocks full of stores, markets, kupols, restaurants, and theaters, and spent the day drifting around, looking at things, buying little except for small items of clothing and toiletries she imagined she might need on the next leg of her journey. Square meter for square meter, this was the finest shopping district in the human universe, drawing its stock from every habitat visited by the Eye, attracting the sophisticated and well-heeled natives of the Great Chain as well as tourists from whichever habitats were currently in reach.

She was feeling a kind of vague ambient pressure—enhanced, no doubt, by the advertising that walled her in on all sides—to buy clothes, or try on jewelry, or get a hairstyle that would make her fit in better on Cradle. That was a place for people more important than Kath Two: brisk, poised paragons in uniforms or smart outfits, speed-walking down corridors in murmuring clusters, exchanging glances across lobbies. Kath One had been much more susceptible to those kinds of social influences and would have been emptying her bank account at this moment, trying to silence the little voice in her head telling her she wasn’t pretty or stylish enough. But Kath One had died at the age of thirteen and been replaced by Kath Two, whose brain had a rather different set of emotional responses. It wasn’t that she was unafraid. Everyone was afraid of something. Kath Two was afraid that she would make the wrong choices, and make a fool and a spectacle of herself, if she tried to dress up to Cradle’s standards. Better to lurk, observe, and merge, as she did when flying in a glider.