Through her nexuses, Washen changed the sky.

The nebula was black for two basic reasons. Enough gas and cold dust were spread out before them to build almost a thousand suns. And even more important, barely a handful of dwarf suns were scattered across a roughly spherical volume some twelve light-years in diameter. Without illumination from within, the cloud was blacker and even colder than it might normally be. If the nebula followed the typical history of such structures, it was on the brink of collapsing into dozens and perhaps hundreds of high-density regions, forming nurseries where stars and brown dwarfs coalesced over the next million little years, followed by an array of new worlds that happily danced with one another and battered each other, violence and mayhem carving new solar systems out of the rawest beginnings.

Centuries ago, when the ship was still firmly on course and untroubled, cursory studies had been made. An officious name was given to the nebula—numbers and letters defining its position, apparent size, and year of discovery. Charts of mass distributions and temperature gradients, plus models projecting a range of likely futures, were accumulated and routinely stored in ship libraries. But the nebula was neither an obstacle nor a likely ground for recruiting new passengers. The occasional hint of life and high technologies might have intrigued some experts, but not the captains. On at least five occasions, the Master had diminished the priority of the work, arguing with conviction and not a small amount of good sense, “We’re approaching a rendezvous with a black hole. That’s where our focus belongs. Not in some little storm cloud sitting on someone else’s horizon.”

Even now, Washen couldn’t fault the Master’s decision. How could a rational mind act on the very remote possibility that this place had importance? Black holes were dangerous for many compelling reasons, particularly those massive black holes living beside aging suns. How could any decent mind dedicated to the service of the Great Ship imagine things going horribly wrong, and going wrong in the precise pattern necessary to put this ship where it was today, on a collision course with a star nursery?

“Infrared,” Washen ordered, specifying frequencies and the resolution.

What looked like a normal dark nebula remained normal by most measures. The bulk of its enormous mass was really quite thin and very cold, composed of molecular hydrogen and helium gas, with tiny flecks of hydrocarbons and silicates and the occasional odd buckyball or two. On average, the cloud was a superior vacuum, and if not harmless, at least endurable. But inside it were pinpricks of heat. The largest heat sources were as big as worlds, and the smallest to date seemed no larger than a major comet. From the radiant signature, it was obvious that the bodies wore elaborate insulation—clinging to precious heat, or perhaps supplying some measure of camouflage. Scattered between the warm bodies were much smaller, much brighter heat sources, each betraying the presence of a fusion engine. Those ships were neither particularly large nor powerful. But if those warm bodies were settlements—little worlds unto themselves—then the unremarkable ships were exactly what one would expect from local trade and slow, patient migrations.

Against the vastness of the Milky Way, the nebula was a fleck of blackness. But when you summed up the volume of warm living space that might exist inside a volume some twelve light-years on a side … well, the numbers were quite simply staggering …

“Microwave,” she ordered, picking her frequencies moment by moment.

When water molecules radiated energy, they had a specific signature, and inside every normal nebula was an abundance of water. But not in this case, it seemed. Barely a third of the expected moisture was visible, and its distribution was highly unusual. When the Submasters examined the recent maps, Aasleen saw the obvious. “Like rivers in space,” she observed. “Look. Ice particles are being collected and shepherded into specific regions. Here, and here, and this knot over here.” The woman had giggled out loud, like a child. “Dopplers give us velocities. Look! The rivers are flowing toward the interior, but not toward the same exact points.”

“How is this done?” the Master had inquired.

“Carefully,” Aasleen reported, admiration mixed with the humor in her voice. “Whoever’s doing this, they’re not being aggressive or energy-intensive. Otherwise, we’d see more heat and other big telltales.”

Washen had imagined trillions of comets, each the size of a closed fist. “Microchines,” she suggested. “Landing on each little world, and then building a tiny mass-launcher—”

“Probably not,” Aasleen interrupted. “There’d be too much dust flying, and pumping energy into each ball of ice would make a second mess.”

“What then?” the Master pressed.

But the chief engineer needed another few moments to make a string of enormous, exacting calculations. Then with her imagination and a long life rich with experience, she devised a simple answer.

“Microchines, yes,” she said with a genuine appreciation. “But what they do … they sit on the surface and generate an electrical charge. Give your pebble or dust mote a robust negative charge, say. Then whoever oversees this business … this construction project … well, they use static charges to push and pull their little bricks wherever they want them. Which is here and here, and these places over there. Do you see? Estimate the volume of these presumed worlds, and compare that figure to the water that seems to be missing from the nebula. They’re not equal, but they’re close to equal. And if you assume that they’ve been gathering up all the dust and asteroids and whatever else is available—”

“How long?” Pamir had asked. “The project to date … from what you can tell … how much time has it taken?”

“At this morning’s rate?” Aasleen used a fingertip, drawing figures on the dark brown palm of her hand. “Ten or fifteen or maybe twenty million years.”

But nebulas didn’t persist that long. Either they collapsed into new stars, or nearby supernovae blew them apart.

“Maybe our neighbors worked faster in the past,” Aasleen conceded. Then she nodded, adding, “What we’re seeing … it could be the tail of a long building project. With these tools and tricks, and the kinds of populations that we can envision …” A look of delighted awe came into her face, eyes shining while a low voice said, “My goodness. You know, now that I think about it, this might not be a natural nebula.”

That earned a sturdy silence from the others.

Finally, Washen asked, “What do you mean? Their engineers have stabilized it somehow? Staving off its collapse, maybe?”

“Maybe,” Aasleen replied.

Then with a nervous laugh, she added, “Or maybe I mean something considerably bigger than that.”

“NEUTRINOS,” WASHEN TOLD her nexus.

Her ceiling erupted into a fierce white glare. What had been a dark cloud was suddenly a kind of ghostly fire—a great if extremely diffuse rain of subatomic particles emerging at the speed of light, particles born inside the fusion furnaces keeping millions of sunless worlds as warm as bathwater.

“Dim it,” she ordered.

But Pamir had felt the light, and with a low grunt, he rolled onto his side, facing her now, one broad arm tossed over his tightly closed eyes.

In the false light of the neutrinos, Washen looked at her lover. He was a huge man blessed with a naturally powerful build, and even in sleep, he carried himself with a tangible indifference to things that most people would consider important. Rank meant little to him. Making him assume the post as Second Chair had proved difficult, and if Pamir enjoyed his newfound authority, he was careful not to show it. A modern person could affect his appearance in nearly infinite ways, and this man wore his own peculiar homeliness without self-doubt or special importance. Yet in every circumstance, he believed in work and serving the ship, and there wasn’t one captain in the ranks who would risk as much as Pamir to care for the passengers, defending them as well as the enormous crew.