She walked across the deck, past the ship’s bell suspended in its elaborate cradle. The huge, misty bulk of Neptune was reflected in the bell’s gleaming surface, and Louise ran her hand over the cool contours of the shaped metal, making it rock gently; the multiple, amorphous images of Neptune slid gracefully across the metal.

From here the Sun was a bright star, a remote point of light; and the blue light of Neptune, eerily Earthlike, bathed the lines of the old ship, making her seem ethereal, not quite substantial — paradoxical, Louise reflected, since the Britain was actually the only real artifact in her sensorium at present.

As the Britain neared the ragged edge of Triton’s ice cap, a geyser blew, almost directly in front of the floating ship. Dark substrate material laced with nitrogen ice plumed into the air, rising ten miles from the plain; as it reached the thin, high altitude wind the plume turned through a right angle and streamed across the face of Triton. Louise walked to the lip of the forecastle deck and followed the line of the plume back down to the surface of the moon, where she could just see the fine crater in the ice at the plume’s base. The geyser was caused by the action of the sun’s heat on pockets of gas trapped beneath thin crusts of ice. Shards of ice were sprinkled around the site of the eruption, and some splinters still cartwheeled through the thin nitrogen atmosphere, slowly returning to the surface under the languid pull of Triton’s gravity.

This was one of her favorite Virtual dioramas, although it was actually one of the least familiar. The capability of her processors to generate these dioramas was huge, but not infinite; she’d deliberately kept the Neptune diorama in reserve, rationing its use over the unchanging centuries, to try to conserve its appeal.

It wasn’t hard to analyze why this particular Virtual scene appealed to her so much. The landscape of this remote moon was extraordinary and unfamiliar, and surprisingly full of change, fueled by the energies of distant Sol; and Neptune’s blue mass, with its traceries of nitrogen cirrus, was sufficiently Earthlike to prompt deep, almost buried feelings of nostalgia in her — and yet different enough that the references to Earth were almost subliminal, obscure enough that she was not tempted to descend into morbid longing. And -

Pixels swirled before her suddenly, a thousand self-orbiting blocks of light. Surprised, she almost stumbled; she gripped onto the rail at the edge of the deck for support.

The pixels coalesced with a soundless concussion into the image of Mark Wu. The projection was poor: the Virtual floated a few inches above the deck, and cast no shadow in Neptune’s pale light.

“Lethe’s waters,” Louise said, “don’t do that. You startled me.”

“I’m sorry,” Mark said. Even his voice was coarse and blocky, Louise noticed. “It was urgent. I had to interrupt you. I — ”

“And this projection’s lousy. What’s the matter with you?” Louise felt her mind slide comfortably into one of its familiar sets — what Mark called her analytical griping. She’d be able to while away a good chunk of the empty day interrogating the processor, picking over details of this representation of Mark. “You’re even floating above the deck, damn it. I wouldn’t be surprised if you start losing the illusion of solidity next. And — ”

“Louise. I said it was urgent.”

She found her voice trailing off, her concentration dissolving.

Mark stepped toward her, and his face enhanced visibly, fleshing out and gaining violet-blue tones of Neptunian light. The processors projecting Mark were obviously trying to help her through this interaction. But the rest of his body remained little more than a three-dimensional sketch — a sign that he was diverting most of the available processing power to another priority. “Louise,” Mark said, his voice soft but insistent. “Something’s happened. Something’s changed.”

“Changed?” Nothing’s changed — not significantly — for nearly a thousand years…

Mark smiled. “Your mouth is open.”

She swallowed. “I’m sorry. I think you’re going to have to give me a bit of time with this.”

“I’m going to turn off the diorama.”

She looked up with unreasonable panic at the remote face of Neptune. “Why?”

“Something’s happened, Louise — ”

“You said that already.”

“The lifedome.” His eyes were fixed on hers.

She felt dreamy, light, almost unconcerned, and she wondered if the nanobots working within her body were feeding her some subtle tranquilizer. “Tell me.”

“Someone is trying to use one of the ports in the lifedome base.” Mark’s eyes were deep, probing. “Do you understand, Louise? Can you hear what I’m saying?”

“Of course I can,” she snapped.

After five centuries without contact, someone was leaving the lifedome. She tried to grasp the reality of Mark’s statement, to envisage it. Someone was coming.

“Turn off the projection,” she told Mark wearily. “I’m ready.”

Neptune collapsed suddenly, like a burst balloon; Triton shriveled into a billion dwindling pixels, and the light of Sol flickered out. For a moment there was only the Great Britain, the undeniable reality of Brunel’s old ship hard and incongruent at the center of this infinity of grayness, of the absence of form; Mark stood before her on the battered deck, his too-real face fixed on hers, reassuring.

Then the Universe returned.

Arrow Maker was falling out of the world.

He sat in the craft — this pod, as Uvarov had called it — with his bow and quiver piled neatly on the seat next to him. His bare legs dangled over his chair’s smooth lip. There was a simple control console, just within his reach before him.

The pod’s walls were transparent, making the cylindrical hull almost invisible. The pod was nothing, less sheltering than an insubstantial dream; the four seats, with Maker and his incongruous, futile bow, seemed to be dropping unsupported through the air.

Uvarov had pointed out the pod to him. Maker had barely been able to see it — a box of translucent strangeness in a world of strangeness.

Uvarov had told him to get into the pod. Maker, without thought, it seemed, had obeyed.

Through the floor of the pod he could see the port approaching. It was a rectangle set in the base of the lifedome, bleak and unadorned, bordered by a line of pale brilliance. He could still see stars through the lifedome base, but he realized now that it wasn’t perfectly transparent. It returned some reflection of the sourceless inner light of the lifedome, making it a genuine floor across the world. Perhaps a layer of dust had collected over the base during the long centuries, spoiling its pristine clarity.

By contrast there was nothing within the expanding frame of the port — nothing, not even Uvarov’s stars. The frame was rising toward him, preparing to swallow him and this foolish craft like an opening mouth.

The port was a doorway to emptiness.

He felt his bowels loosen. Fear was constantly with him, constantly threatening to erupt from his control…

Spinner’s voice sounded small, distorted, emanating from the air. “Maker? Can you hear me? Are you all right?”

He cried out and gripped the edges of his seat. His throat was so tight with tension he couldn’t speak. He closed his eyes, shutting out the huge, bizarre unrealities around him, and tried to get some control. He lifted his hands to his waist; he touched the liana rope Spinner had wrapped around him as a good luck talisman, just before his departure.

“Maker? Arrow Maker?”

“…Spinner,” he gasped. “I can hear you. Are you all right?”

She laughed, and just for a moment he could visualize her round, sardonic face, the way she would push her spectacles up her short nose. “That’s hardly the point, is it? The question is, are you all right?”