On the surface at Brinkmann IV (“Moonlight”), in IC4756, 1300 light-years from Earth.

Autumn 2230.

IT WAS THE most majestic series of structures David Collingdale had ever seen. Steeples and domes and polygons rose out of ice and snow. Walkways soared among the towers, or their remnants. Many had collapsed. There were pyramids and open squares that might once have been parks or courtyards. An obelisk anchored the center of the city. It was a place out of time, frozen, preserved for the ages, a landscape that might have been composed by Montelet. A place of crystal and glass, and, in a kinder age, of flowering trees and shaped hedges and beckoning forest. Catch it at the right time, when its giant moon, half again as big as Luna, was in the sky, and one might have thought that here was the celestial city, Valhalla, Argolis, El Dorado by night.

It looked too ethereal to have actually served as a home for a thriving population. Rather, Collingdale could not get away from the sense that it had been intended by its builders as a work of art, to remain unused, to stand as a monument rather than a city. Several of the towers had collapsed, broken fragments rising out of a thick carpet of snow. Its name was unknown, so they called it Moonlight, the city and the world and the sense of something lost.

A bleak wind howled down the empty streets, chilling him even in the e-suit, which was apparently not functioning properly. He’d see to getting it adjusted when he got back to the dome. Wouldn’t want to have it fail out here at twenty below.

The sun was struggling to get above a flat mountain range. Several thousand years ago, something had gone wrong with it. Abrams had explained it to him, a surfeit of metals or some such thing. Just temporary, he’d insisted. Be back to normal, he expected, in another few thousand years. Not that it would matter.

He was at the equator, where the remnants of the once-global civilization had fled. There were other cities, most in areas that had once been equatorial, some buried in snowfields, still others frozen behind walls of ice.

He and his team knew little yet about the race that had lived here, except that they were a long time dead, and their architecture rivaled anything man had produced. Crystal bridges thrown across mighty rivers, hyperbolic domes, broad walkways in the sky. All frozen now, the bridges as well as the rivers, the crystal as well as the spirit.

It was perhaps a hard irony that Moonlight, which had thrived and died about the time humans were rolling stones out of quarries to build the first pyramids, would probably have remained undiscovered indefinitely had it not been that it was about to receive an unwelcome visitor. A survey ship, the Harry Coker, had been watching an omega, one of the monstrous clouds that drifted in waves out of the galactic core, and which seemed bent on destroying any civilization in their path. The Coker was anxious to see how the cloud would fare in the complex gravity field of a planetary system, when it spotted evidence of cities on the fourth planet.

Collingdale squinted into the hard gray sky. The cloud was visible from late afternoon until shortly after midnight. It was up there now, partially obscured in the glare of the sunset. In the daytime it looked utterly harmless, a large dark thunderstorm, perhaps, like a million others he had seen in his lifetime. But this one rose and set with the sky beyond the atmosphere. It always described the same path across the heavens and it kept getting bigger.

The omega clouds were old news. They’d been discovered a quarter century earlier. Although no one had ever seen them attack a city, they were tied to massive destruction in ancient times on Quraqua, Beta Pacifica III, and two other worlds. Objects with a wide range of geometric shapes had been floated in front of the omegas, and humans now knew beyond any question that designs not found in nature could expect to draw lightning bolts.

Nobody understood how or why. No one knew where they came from. And few seemed to feel it was likely we would ever find out.

Until now, no one had seen a cloud change course and glide into a planetary system. No one had seen a city under attack.

It was fortunate nobody lived on Moonlight. The inhabitants had obviously been overwhelmed by the ice age brought on by the instability of their sun. Best estimates were that there’d been no one there for about two thousand years.

COLLINGDALE HAD GROWN up in Boston with an alcoholic mother and a missing father, who, his mother insisted until the day of her sodden teary death, had gone west on business and would be back any day. He’d spent two years in an orphanage, been adopted by a pair of religious fanatics, run away so many times they’d eventually implanted a tracker, and—despite everything—won a scholarship from the University of Massachusetts. He’d taken a degree in archeology, taken private flying lessons on a whim, and, as he liked to think of it, never again touched ground. Eventually he’d decided that flights between Chicago and Boston were too confining. He’d learned to pilot the superluminals, had taken the command seat for several major corporations and the Academy, had gotten bored hauling people and supplies back and forth through the void, gone back to school, and specialized in a discipline that, at that time, lacked subject matter: xenology.

In the meantime he’d attended the funerals of both his foster parents, who’d died a year apart, the one unable to live without the other. They’d refused longevity treatments on the grounds they were not God’s plan. They’d never given up on him, even though they disapproved of the directions his life had taken. He’d stopped going home during the last years of their lives because they kept telling him they forgave him and were sure God would as well.

He didn’t know why they intruded on his thoughts while he gazed across the city. He would have liked them to see Moonlight. Surely they would have been caught up in its majesty, and they might have understood what his life was about.

THE OMEGAS ROUTINELY hurled lightning bolts at perpendiculars. Any object designed with right angles, or sharp departures from nature’s natural arcs, could expect to become a target.

It had seemed an old wives’ tale when the stories first came back. Collingdale recalled that the scientific community, almost to a person, had scoffed at the reports. The notion that clouds could somehow navigate on their own seemed absurd. That they could bump up to high velocities more absurd still. Most had not accepted the idea until the one approaching Moonlight, the Brinkmann Cloud, had changed course, begun to slow down, and headed insystem. That was four years ago.

The claims had been so outlandish that nobody who cared about his reputation had even tested them. But once the Brinkmann showed its ability to navigate, researchers had come, and an attempt to explain the impossible had begun. It had begun with the discovery of nanos in samples taken from the omega.

Were the clouds natural objects? Or artificial? Did the universe disapprove of intelligent life? Or was there a psychotic force in existence somewhere? Or, as his parents had thought, was God sending a warning?

“You coming, Dave?”

They’d cut their way into the base of the northeastern tower, and Jerry Riley was standing aside, leaving for Dave the honor of being first person to enter the structure. He clapped a few shoulders, strode down between banks of dugout snow, paused at the entrance, put his head in, and flashed his lamp around.

The interior was as large as New York’s main terminal. The ceiling soared several stories. Benches were scattered throughout the area. Sleek metal columns supported balconies and galleries. Alcoves that might once have been shops were set into the walls. And there was a statue.

He took a few steps inside, scarcely daring to breathe. They knew what the natives looked like because they’d found remains. But they’d never seen any depictions of them. No sculptures, no graphics, no engravings. How odd it had seemed that a species so given to art had given them no copies of its own image.

The others filed in and spread out around him, all enamored of the statue. Jerry raised his lamp slowly, almost reverently, and played the light across it. It was a feline. Claws were replaced by manipulative digits, but the snout and fangs remained. Narrow eyes, in front. A predator. But it wore a hat, rather like an artist’s beret, angled down over one eye. It was decked out in trousers, a shirt with long fluffy sleeves, and a jacket that would not have looked out of place in Boston. A bandanna was tied around its neck. And it sported a cane.

One of the women giggled.

Collingdale couldn’t suppress a smile himself, and yet despite its comic aspect, the creature displayed a substantial degree of dignity.

There was an inscription on the base, a single line of characters, executed in a style reminiscent of Old English. It was probably a single word. “Its name?” someone suggested.

Collingdale wondered what the subject had done. A Washington? A Churchill? A Francis Bacon? Perhaps a Mozart.

“The architect,” said Riley, short and generally cynical. “This is the guy who built the place.” Riley didn’t like being out here, but needed this last mission to establish his bona fides with the University of Something-or-Other back home. He’d be an inspiration to the students.

It was odd how the intangibles carried over from species to species. Dignity. Majesty. Power. Whether it was seen in an avian or a monkey, or something between, it always had the same look.

His commlink vibrated against his wrist. It was Alexandra, who’d arrived two days before on the al-Jahani with a cargo of nukes, which she’d been instructed to use in an effort to blow away the cloud. Nobody believed it could be done, but no other course of action offered itself. The cloud was simply too big, thirty-four thousand kilometers in diameter. A few nukes would have no effect.

“Yes, Alex. What’ve you got?”

“It’s still slowing down, Dave. And it’s still on target.”

“Okay.”

“It’s coming in on your side of the world. Looks as if it’s homed in on your city. We’re going to set the bombs off tonight. In about six hours.”

The omega was slowing down by firing jets of dust and hydrogen forward. Riley thought it might also be twisting gravity, but there was no evidence yet to support that idea. The only thing that mattered was that, however it was managing things, the cloud was going to arrive right on top of Moonlight.

THEY WANDERED FOR hours through the underground. There was a network of smaller chambers connected to the large area. They found an endless number of chairs, bowls, radios, monitors, plumbing fixtures, conference tables. Artifacts they couldn’t identify. Much of it was in surprisingly good condition. There were boxes of plastic disks, undoubtedly memory storage units. But electronic records were fragile. Early civilizations carved their history onto clay tablets, which lasted virtually forever. More advanced groups went for paper, which had a reasonable shelf life, provided it was stored in a dry place and not mishandled. But electronic data had no staying power. They had not yet been able to recover a single electronic record.