Over time, comets delivered a skim of water and air, and the naked iron rusted enthusiastically. Without a rocky mantle there was none of the magmatic churning that characterized Earth’s dynamic geology. Still, simple life had come here, brought by the comets, settling into oceans that gathered in impact-basin hollows.

And later, humans arrived.

Alia was discovering she wasn’t interested in planets. She had grown up on a ship, a human-made environment. The Nord was a small, liveable place, built to a human scale, where everybody knew everybody else. And the Nord was fluid, every aspect of its design shaped by human whim. As a small child she had loved to spend time in the Nord’s museum, where there was a display of all the ship’s morphologies since its launch long ago, reconstructed from records, or archaeological traces in the Nord’s fabric. As the millennia ticked by the vessel had mutated and morphed like a pupa writhing in its cocoon, every aspect of its geometry shaped by its crew.

But a world was different, weighed down by its own vast geological inertia. Why, most of its mass was locked up in its interior, useless for anything but exerting a gravity field you could have replicated with the most basic inertial adjustor! And it was static in time. A through-the-ages diorama of the Rustball would have been very dull, she thought: nothing but rocks, broken here and there by the transient flickering of green.

If the Rustball had started out dull, its human colonists hadn’t done much with the place, Alia thought. The plain drabness of the human world here was striking. The different towns, though separated by hours of surface travel, were very similar in their bland, squat architecture; there was no sense of local identity. And there was no art that she could see, nothing beyond the functional.

She probed Bale gently about all this. He would only say: “If everywhere’s the same, why bother traveling?”

“Lethe, I hate planets,” she said. “No offense.”

“None taken,” Bale said blandly.

It was a relief when they reached the ocean.

The water pooled in a complicated multiple basin cut in the iron by a series of impacts. On a shore of hard, red-rusted iron, waves broke; driven by the higher gravity the waves were low but fast-moving.

She was surprised to see people here, gathered in little parties along the shore. Bicycling vendors sold food, water, souvenirs, and simple toys. It was a happy place, as happy as she had seen on the Rustball; people were enjoying themselves. But as she walked through crowds of running children, harassed parents, and languid lovers, something was lacking, she thought. It took her a while to realize that there was no music to be heard, not a single note.

Following Bale’s lead, Alia walked to the edge of the water and stripped down. Alia couldn’t help studying Bale’s body, the broad limbs, the banks of muscles on his belly.

He caught her staring.

“I apologize,” she said. “It’s just that our bodies are so different.”

So they were. She was so much taller and slimmer, her arms almost as long as her legs, and her fur was languid in the heavy gravity. By comparison Bale was squat, broad, shaped by a lifetime of battling the relentless pressure of gravity. His arms were short, massive, but inflexible at the shoulder and joints. His spine was rigid, too, a pillar of bone. This wasn’t a world where you would do much climbing, she thought; Bale was actually more truly bipedal than she was.

“We’re different because we live on different worlds,” Bale said.

“So we do.”

“But Reath sent you here because we aren’t too different, because we are similar.”

“He did?”

Bale smiled. “Unmediated Communication is challenging enough without a dose of alienness on top.”

She wondered, then, about how strange a human could get.

Naked, side by side, they walked into the ocean. The water was fast-moving and turbulent. Her fur, soaked, drifted around her. Alia had swum before, but only in zero-gravity bubbles on the Nord, where it was no more than a hundred meters or so to the nearest meniscus. It was very strange to slide into a body of water orders of magnitude more voluminous, a bottomless pit of it. Bale’s cursory warnings about treacherous currents and undertows did nothing to reassure her. It was an unexpected relief, though, when the water was at last deep enough for her to lift her feet from the bottom and float. She felt her bones, her muscles relax as they welcomed their first respite from gravity since orbit.

All around her the stocky bodies of Rusties, adults and children, bobbed in the water. They laughed and played. Even on this drab world the ocean was a place of pleasure. Perhaps, she thought, even after hundreds of millennia of adaptation, the people’s bodies were responding to deep cellular memories of a primordial ocean that lay far away and deep in time. But when the water got into her mouth, it was very salty, with the bloodlike taste of iron.

Bale floated beside her, watching her.

“Bale, you said you don’t travel much because everywhere is the same. Maybe that’s true, here on the Rustball. But aren’t you curious about other worlds?”

He shrugged. “People are more interesting than worlds. Anyhow, we Witness. We find out about other people that way.”

“Everybody Witnesses, all across the Galaxy. It’s another thing we have in common. It is the mandate of the Transcendence.” This was what Reath had told her.

“Yes.” But Bale was watching her, suddenly intense. “What do you think about the Transcendence?”

“I don’t know enough about it,” she said. “It’s just there. Like the weather, on a planet like this.”

“Yes. And the Witnessing, the Redemption?”

“I don’t know. Why are you so interested in that?”

“There are people,” he said carefully, “who question the value of the Redemption.”

“There are? Do you?”

He studied her a moment more, then seemed to come to some conclusion. “You are innocent. I like that.”

“You do?”

“Yes. And I like Witnessing — the act of it, anyhow, if not the implications of the program. I told you I am interested in people.”

She asked impulsively, “And are you interested in me?”

He smiled. “Sex would not be out of the question. I would take great care not to crush your ribs, snap your limbs, or inflict other harm.”

“I’m sure you would.” She moved toward him, not touching yet, just staring at him, feeling his massive presence in the water. She had been with non-ship-born before. There was always a fascination between different human breeds, a deep longing for some kind of genetic exploration. Or maybe it was just simple curiosity.

She moved closer. He opened his mouth, and she ran her tongue over the edge of his teeth-plate. His arms were as powerful as she imagined, his hands as gentle. And in the water her zero-gravity litheness pleased him.

I booked Tom into a hotel at Heathrow.

A day ahead of his arrival, too anxious to hang around in York anymore, I took a train journey back to Heathrow myself. I was the only passenger in a pod bus that rolled in a stately fashion over abandoned kilometers of roadway. The hotel was a long way out from the terminals, a measure of how busy this airport had once been. The hotel itself was a kind of extension of a vast multistory parking lot dating from the second half of the twentieth century, the age of monumental automotive architecture. It was as if the areas set aside for humans had been an afterthought. Now the cars had gone, but the hotel lingered on.

There were no lines at check-in. I had the distinct impression that I was the only guest. It was an uneasy feeling, as if the whole hotel was a sham, an immense trap for unwary travelers.