But they weren’t paying any attention to Pirius. He walked toward the dome’s clear wall and gazed out at Pluto.

There were clouds above him, wispy cirrus, occluding bone-white stars: they were aerosol clusters, according to Nilis’s briefing material, suspended in the atmosphere of nitrogen and methane. The landscape was surprisingly complex, a starlit sculpture of feathery ridges and fine ravines — although perhaps it wouldn’t be so interesting away from Christy. Sol was a point of light, low on the horizon, wreathed in the complex strata of a cloud. The inner system was a puddle of light around Sol, an oblique disc small enough for Pirius to cover with his palm. It was strange to think that that unprepossessing blur had contained all of man’s history before the first pioneers had risked their lives by venturing out to the rim of Sol system, and beyond.

Charon hung directly over Pirius’s head. It was a misty blue disc, six times the size of Luna as seen from Earth. He had been trained for spectacles like this, but he flinched from the sight of a world hanging over him like a light globe. Charon’s surface looked pocked. No doubt there was plenty of impact cratering, even here in this misty, spacious place, but many of the gouges he could make out, even with his naked eyes, were deep and quite regular.

“They are quarries.”

He turned. One of Draq’s gaggle of followers had come to stand beside him. She was evidently a woman; her face, turned up to the light of Charon, had a certain delicacy about the brow, the cheekbones.

“Quarries?”

“My name is Mara. I work with Draq.” She smiled at him, then looked away. Though she seemed rather awestruck, she evidently didn’t share Draq’s giggling foolishness. “Michael Poole himself came here, thousands of years ago. Our most famous visitor — before you, of course! He traveled from Jupiter on a GUTdrive ship, and he and his engineers used Charon ice to make exotic matter—”

“To build a wormhole mouth.”

“Yes. Here, Poole completed his cross-system wormhole transit network. When it was done, why, you could travel from Pluto all the way to Mercury almost as easily as you walked through that tunnel from your ship… there.” She pointed up toward Charon’s limb. Pirius made out a spark of light, no brighter than the remote stars, but it drifted as he watched. “That’s Poole’s interface station — or the ruins of it.” The Qax had of course shut down Poole’s venerable spacetime engineering, and over the millennia since, most of his interface stations had been broken up, their raw material reused.

Not here, though; nobody had bothered to do even that much.

Mara defended her adopted world. “It’s true nobody lives here — nobody but us, that is. The Coalition has tried to establish settlements, but they always fail. There has never been enough to keep people here, no resource you couldn’t find on a thousand Kuiper moons, and in more shallow gravity wells at that. But we do have our marvels.”

Pluto’s orbit was so elliptical it sailed within the orbit of Neptune. At the closest approach to Sol, the atmosphere expanded to three planetary diameters. Then, when Pluto turned away from Sol and sailed into its two-hundred-year winter, the air snowed down.

Mara described all this lyrically. She seemed eager to have someone new to talk to. Those exiled here called themselves Plutinos, she said. Pirius was drawn by her sense of this remote world, which swam through immense, empty volumes while slow, subtle seasons of ice came and went.

“Ah,” she said now. “Look up.”

Puzzled, he glanced up at the looming, misty shape of Charon. “I don’t see anything.”

She waved a hand, and the light intensity in their corner of the dome reduced.

As his eyes dark-adapted, more stars came out, peering around Charon’s limb, and he made out more detail on the moon’s mottled surface. He leaned close to Mara’s shoulder to see, and his cheek brushed the coarse cloth of her robe. There was a mustiness about her, but he was not repelled, as he had been by Draq; she was strange, he thought, even eccentric, but oddly likeable. He wondered what her story was, how she had come to be assigned to a covert establishment on this remote world.

She pointed again. “There — can you see? Look along my arm.”

Suddenly he saw it, stretching between Pluto and its moon. Only dimly visible in Sol’s reduced light, a glimmer here, a stretch of arc there, it was nothing like the Bridge that had been erected between Earth and its Moon — this was finer, more elegant, more organic than that. But it was a line that spanned worlds nevertheless.

Pirius had heard of this. “It’s natural, isn’t it?”

“It’s spiderweb,” she breathed. “Pluto-Charon is swathed in spiderweb.”

Nilis came bustling up. “One of Sol system’s more memorable spectacles,” he said. “And it is only possible here, where both worlds are locked face to face.” He slapped Pirius on the back. “But we aren’t here to sight-see, Ensign! We have work to do.”

Reluctantly they rejoined the rest of the group, who were crowding into a flitter.

The journey was going to be long, Pirius was told; they would be taken right around the curve of the world. He was dismayed that the little craft was already full of these exiled scientists’ peculiar odors.

As they took their places, Mara sat beside Pirius. She said, “You must come back in the spring, when the spiders of Pluto come out to sail between the worlds and build their webbing all over again.”

“Spring? When’s that?”

“Oh, about another seventy years…”

The flitter lifted smoothly.

They flew silently through the geometry of the double worlds.

Pirius, retreating from the chattering group, spent the journey preparing a long Virtual message to Torec, who was stuck at Saturn, still working on the development of the CTC processor. He fixed a cloak of antisound around himself so the Plutinos would not be offended by what he had to say about them.

When the cramped little craft began at last to descend, Charon was long lost beneath the horizon. There was nothing to be seen here, nothing but the fractured, ancient ground. But before the flitter, the ground rose to a ridge. Beyond this, evidently, was what they had come to see.

Draq said, “We’ll walk from here, rather than fly. It’s best if you come to the facility yourself. There’s nothing quite so striking as a purely human experience — don’t you think, Commissary?”

Pirius was glad to seal up his skinsuit, which smelled of nothing but him. But the Commissary, as usual, demurred, and insisted that a Virtual projection would do just as well for him.

So Pirius stepped out onto the surface of yet another world. Sol was halfway up the sky, a diamond of light.

He took a few experimental steps. Gravity was only a few percent of standard. The ice crunched, compressing, but the fractured surface supported his weight. Pluto ice was a rich crimson laced with organic purple. He made out patterns, dimly, in the ice; they were like bas-relief, discs the size of dinner plates, with the intricate complexity of snowflakes. The suit’s insulation was good, but enough heat leaked to send nitrogen clouds hissing up around his footsteps.

The group began to climb the shallow ridge. There were five of them out on the ice, if you included Nilis. Draq led the way, and Pirius and Nilis followed, with two other Plutinos, including Mara, who walked with Pirius. Nilis floated serenely a few centimeters above the ice, barefoot and without so much as a face mask, once more blithely ignoring all Virtual protocols. It was crassly discourteous, Pirius thought, irritated. But the Plutinos were too polite, or too cowed, to mention it.

Where the ground was steeper, the frost covering had slipped away. The “bedrock” here was water ice, but ice so cold it was hard as granite on Earth, and Pirius thought he could feel its chill through the heated soles of his boots. But it wasn’t slippery; at Pluto’s temperatures even the heat his suit leaked wasn’t sufficient to melt the surface.