And that was the hard part. That, she reflected, was the point from which the endless strings of martyrs strewn across mankind’s bloody history had failed to return. And since then he’d kept functioning — contributing to the mission.

She grinned. “I think you’re tougher than you look, Planner Milpitas. I mean, you have managed to break out of the prison of your past…”

He turned. “But the past is not a prison,” he said softly. “The past is altered, constantly, by our actions in the present. Every new act revalues the meaning of the past…”

She was surprised. “That sounds like the surface of a deep philosophy.”

“Deep, and old,” he said. He eyed her, the tracery of scars over his scalp vivid in the flat light of the loading bay. “We in Superet were never one-dimensional oppressors, Lieserl. We saw ourselves as preserving the best of humanity’s wisdom, and we sought constantly to interpret our present and future in history’s light…”

She grunted. “Hmm. Interesting. Perhaps the notion of a fluid past, recast in the light of our changing assumptions, is the only philosophy which will allow a race of immortals to stay sane. Maybe I’m still underestimating you, Milpitas.”

He touched his control bar and, gently, rose into the air. His face was impassive. “Perish the thought,” he said drily.

The Universe-image expanded, focusing on a comparatively small volume; Spinner studied a nondescript chunk of cosmic foam, a collection of threads, voids and sheets of shining matter.

“Okay, Spinner-of-Rope: here’s a three-dimensional map of our neighborhood. The voids are around a hundred million light-years across, on average.

“Now here’s a local landmark — a famous void called the Hole in Bootes, two hundred million light-years across — and, look, here’s the Great Wall: the largest coherent structure in the Universe, a sheet of galaxies five hundred million light-years long.” Louise paused, and when she spoke again her voice was darker, tinged with the resentment and half suppressed anger Spinner had come to recognize. “Of course the Wall isn’t quite the tourist site it was when I was a girl,” she said sourly. “The damn photino birds have been active there as well… All across the Wall, as far as we can observe, there’s evidence of bird degradation.”

Spinner allowed herself to smile. She could imagine what Louise was thinking. Damn it, it’s our Wall!

Louise was saying, “This cloud” — a mist fragment the size of Spinner’s hand, labeled by a small red arrow — “is the Virgo Cluster. Our local supercluster.” A small region within the Virgo cloud began to flash yellow, and a straight blue line snaked out of the yellow clump, piercing the heart of the Virgo. “The little yellow volume is the Local Group, where Sol is,” Louise said, “and the line represents our journey so far with the nightfighter: right through the middle of the Virgo supercluster.”

Spinner grunted. “Not very far.”

“Oh, come on, Spinner; think about the scale of this picture!

“Now look at this,” Louise said. Small, lime-green vector arrows appeared, bristling over the dusty surface of the Virgo Cluster. “See that? The whole of our supercluster is moving through space — and it’s at a significant speed, a million miles an hour or more. So fast that the motion was even observable from Earth — it imposed a Doppler shift on the whole Universe, Spinner: on the microwave background radiation itself.”

Now more velocity arrows appeared on another massive cluster close to the Virgo Cluster. “There’s another super-cluster, called Hydra-Centaurus,” Louise said. “And guess what: that’s streaming in the same direction as the Virgo.”

Velocity arrows bristled now all over the foamy region of space… and all the arrows, Spinner saw, pointed inwards, to an anonymous region at the heart of the three-dimensional diagram.

And the projected blue line of the nightfighter’s voyage reached toward the center of the immense implosion.

“I know what that is,” Spinner breathed. “At the center of the implosion. That’s the Great Attractor.” The place all the galaxies are falling to…

“Yes. There seems to be a mass concentration there, attracting galaxies across hundreds of millions of light years. The Attractor is a hundred and fifty million light years from Sol, and with the mass of ten thousand galaxies…”

Staring into the toy Universe, Spinner-of-Rope felt her heart flutter. “And if it really is an artifact — ”

“If it is, then it’s an artifact so massive it’s drawing in superclusters like moths, Spinner; so massive it’s actually counteracting the expansion of the Universe, in this part of space… It’s an artifact beyond our imagination.”

Yes, thought Spinner. Beyond imagination. And that’s where we’re heading…

“I don’t know why you had to drag me up here, into the forest,” Louise grumbled. “Not now. Couldn’t you wait until you were sure of your data?”

Mark said, “But the data — ”

“Is partial, and incomplete, and hardly conclusive. What have you got — just two double images?”

“But the spectral match of the double galaxy images is almost perfect, in each case. I tell you it must be string,” Mark insisted.

“And I’m telling you that’s impossible,” Louise growled. She felt her irritation rise. “How could there be cosmic string in the middle of a void like this?”

Uvarov raised his skull-like face and cackled, relishing the conflict.

The three of them were suspended just below the forest skydome. Louise was on a zero-gee scooter, and Uvarov had been strapped into a stripped-down life support chair attached to three of the flexible little scooters.

Mark, irritatingly, was choosing to manifest himself as a disembodied head, twice life-size, hovering in the air. “How’s Spinner-of-Rope?” he asked Louise.

She grunted. “Bearing up. We’re thirty-three days into the mission, now thirty-three days for Spinner in that couch. And the last ten of them inside this damn hole in the sky.”

“Well, this is really a pretty exciting part of the journey,” Mark said. “We’re crossing the edge of the greatest cosmological void ever detected: more than two hundred million light-years across. As far as we can tell, we’re the only scrap of baryonic matter in all that immensity. That’s an exciting thought even without my evidence of cosmic string…”

“Not exciting for Spinner,” Louise said drily. “For her this void is nothing but sensory deprivation.”

“Hmmm,” said Uvarov. “The Universe as an immense sensory deprivation tank… maybe that’s a good image to sum up the photino birds’ cosmic handiwork.”

Now schematic graphics of remote galaxies — sheets of them, at the boundary of the huge void — peppered the dome with splashes of false color; here and there fragments of text and supplementary images were interspersed amid the insect like galactic swarms.

Mark’s head swiveled around toward Louise. “Look, I’m sorry you don’t think it’s appropriate for me to have dragged you up here. Maybe I should have waited for proof of the string’s existence. Well, I didn’t realize we were out here to do science. I thought we were trying to find ways to stay alive — to anticipate what we’re up against. And that means reacting — and thinking, Louise — as quickly and as flexibly as possible. All right, maybe I’m guessing. But — what if it is cosmic string out there? Have you thought about that?”

Louise turned her face, uncertainly, up to the dome. “If it is string — here — then, perhaps, we’re heading into something even more extraordinary than we’ve anticipated.”

Uvarov chuckled. “Perhaps we should stick to the facts, my dear Mark.”

“There are no facts,” Louise said. “Only a handful of observations. And — across distances measured in hundreds of millions of light-years, and taken from a platform moving through a hyperdrive journey — they’re damned imprecise observations at that.”