There were some books, which had not been stored properly. Nevertheless, they gathered them into plastic containers. They’d been in the area several weeks, but there was a special urgency about this visit. The cloud was coming. Anything they did not carry off today might not survive.

The walls were covered with engravings. Collingdale assigned one of his people to record as many of them as she could. Some of it was symbolic, much was graphic, usually with bucolic themes, leaves and stems and branches, all of which, when the sun came back, might grow on this world again.

Stairways and shafts rose high into the structure and descended to lower floors, which were encased in ice. “But that might be a huge piece of good luck,” Collingdale told Ava MacAvoy, who looked unusually attractive in the reflected light. “It should survive the cloud, whatever happens to the rest of the city.”

They went back outside. It was time to leave, but Collingdale delayed, taking more pictures, recording everything. Ava and Riley and the others had to pull him away.

The cloud was setting by then, and Collingdale wished it was possible to halt the planet on its axis, keep the other side between the omega and the towers. Hide the city.

Damn you.

He stood facing it, as if he would have held it off by sheer will.

Ava took his arm. “Come on, Dave,” she said. “It’s getting late.”

THEY RETREATED TO the dome, which had served as their base for the better part of a month. A lander waited beside it. The dome was small, cramped, uncomfortable. They’d brought out too many people, and could in fact have brought several shiploads more. Everyone had wanted to come to Moonlight. The Academy, under time pressure, had tried to accommodate the requests as best it could. It should have said no. That was partly Collingdale’s own fault for not demanding they cut things off.

They’d filled the dome with artifacts and shipped them topside to the al-Jahani, which now carried a treasure trove of mugs and plates and table lamps and electronic gear, and materials far more esoteric, objects whose function defied analysis. Other pieces were now being loaded. There was more than the lander could handle, but they’d stacked the rest in the dome, hoping that it would be safe there.

Collingdale waited until everybody else was on board—there were seven of them, excluding the pilot—took a last look around, and climbed in. The omega was almost down. Only a black ridge of clouds was visible in the west, and a few streaked plumes soared above the horizon. The pilot started the engines, and the lander rose. Nobody said much.

Jerry commented how scary it was, and Collingdale couldn’t restrain a smile. He himself was of the old school. He’d started his archeological career in Iraq, had been shot at, threatened, deported. When archeology went interstellar, as it had a half century ago, it had become, curiously enough, safer. There were no deranged local populations defending sacred tombs, no warlords for whom the security payment might be insufficient, no national governments waiting to collapse with dire consequences to the researchers, who might be jailed, beaten, even killed. There were still hazards, but they tended to be less unpredictable, and more within the control of the individual. Don’t take foolish chances, and you won’t get burned. Don’t stay too long in the submerged temple, as had famously happened to Richard Wald twenty-some years earlier, when you know the tidal wave’s coming.

So Collingdale was getting his people out in plenty of time. But it didn’t prevent them from thinking they were having a narrow escape from something dire. In fact, of course, at no time were they in danger.

He was looking down at the receding city when the pilot informed him he had an incoming transmission from the al-Jahani. He opened the channel, turning up the volume so everybody could hear. Alexandra’s blond features appeared on-screen. “We’ve launched, Dave,” she said. “All twelve running true. Detonation in thirty-eight minutes.”

The missiles were cluster weapons, each carrying sixteen nukes. If the plan worked, the missiles would penetrate two thousand kilometers into the cloud and jettison their weapons, which would explode simultaneously. Or they would explode when their electronics failed. The latter provision arose from the inability of researchers to sink probes more than a few kilometers into the clouds. Once inside, everything tended to shut down. Early on, a few ships had been lost.

“Good luck, Alex,” he said. “Give it hell.”

The lander, powered by its spike technology, ascended quickly, traveling west. The cloud began to rise also. The flight had been planned to allow the occupants a view of the omega when the missiles reached the target.

Collingdale ached for a success. There was nothing in his life, no award, no intellectual breakthrough, no woman, he had ever wanted as passionately as he wanted to see Alexandra’s missiles blow the son of a bitch to hell.

They climbed into orbit and passed into sunlight. Everyone sat quietly, not talking much. Riley and Ava pretended to be examining an electronic device they’d brought up, trying to figure out what it was. Jerry was looking through his notes. Even Collingdale, who prided himself on total honesty, gazed steadfastly at a recently recorded London conference on new Egyptian finds.

The cloud filled the sky again.

“Three minutes,” said Alex.

THEY COULDN’T SEE the al-Jahani directly. It was too far, and it was lost somewhere in the enormous plumes that fountained off the cloud’s surface like so many tendrils reaching toward Moonlight. But its position was known, and Bill, the ship’s artificial intelligence, had put a marker on the screen. They could see the cloud, of course, and the positions of the missiles were also marked. Twelve blinking lights closing on the oversize gasbag. Collingdale amused himself by counting the weapons.

“Thirty seconds to impact,” said the pilot.

Collingdale let his head fall back. He wondered whether one could achieve impact with a cloud.

Ava watched the time, and her lips were moving, counting down the seconds.

“They’re in,” she said. Someone’s hand touched his shoulder. Gripped it. Good luck.

Riley adjusted his harness.

Collingdale, knowing his foster parents would have been proud, muttered a prayer.

“They’ve gone off.” Alexandra’s voice. “Too soon.”

There were a few glimmerings along the surface of the cloud. But he saw no sign of disruption.

“It might take a while before we can really see anything,” said Riley, hopefully.

The hand on his shoulder let go.

“You’re right,” said one of the others. “I mean, the cloud is so big.”

“The bombs had to do some damage. How could they not?”

“Maybe just screw up the steering mechanism. Hell, that would be enough.”

The glimmering got brighter. Collingdale thought he saw an explosion. Yes, there was no doubt of it. And there. Over there was a second eruption of some kind. They watched several patches grow more incandescent. Watched the cloud pass overhead. Watched it begin to sink toward the rim of the world.

The explosive patches darkened.

On a second orbit, they were still visible, smoldering scars on the otherwise pacific surface of the omega.

“I don’t think it’s going to work,” said the pilot.

ON THE THIRD orbit, they rendezvoused with the Quagmor, the vessel that had transported them to the system. The mood on the ship was dark, and everybody was making comments about having made a good effort. Just so much we can do.

Alexandra reported that the omega was still on course for Moonlight. “We didn’t get much penetration. There’s still a chance we might have done some damage that just doesn’t show. I mean, if we blew up the internal skunk works, how would we know? So don’t give up, Doc.”

He didn’t. But the view was unsettling. The jets reached out, arcing as if to encircle the planet. The omega was a malignant force, a thing out of religious myth, an agency beyond understanding.

The al-Jahani maneuvered around the fringes of the cloud, trying to record as much of the event as it could. Collingdale went to his quarters, slept, got up, slept some more. The cloud closed and, as the city rotated into position, made contact directly above. Winds howled. Lightning ripped through the skies. Tornadoes formed.

It was just after sunset.

Collingdale could hardly bring himself to watch. Electrical discharges had been growing in the cloud, had become more intense as it drew nearer. The storm gathered force, but the towers stood, and the planet rotated, moving the city directly to ground zero and then past. And for a while he hoped it would get clear. But without warning a gigantic bolt tore though the cloud and hammered the city. The chess-piece structures seemed to melt and blacken and sink into the ice. Sprays of pebbles rattled against them, and something blasted into the base of one of the corner towers. The tower shuddered and began to lean precipitously. Other buildings collapsed or were blown away. Once, twice, they lost the picture as satellites were neutralized. Lightning ripped out of the night, scorched the diamond steeples and the crystal polygons. Hurricane-force winds hurled black dust across the snowscape. A few rocks fell from the sky, plowing into glass and crystal. It needed only a few minutes, and when it was over, a ground blizzard buried everything.

Collingdale was hardly a violent or even a confrontational man. He hadn’t been in a loud argument as far back as he could remember. But in those moments he would have killed. Rage spilled out of his soul, sheer fury driven to excess by his helplessness.

The cloud wrapped itself around the world, around Moonlight, and it found the other cities. It struck them in a display of sheet lightning, forked lightning, chain lightning, and fireballs. Collingdale couldn’t get away from it. He wandered through the ship, downing glasses of rum, extreme behavior for a man who seldom drank. He couldn’t stop moving, from the bridge to the mission center to the common room to his cabin to Riley’s quarters. (“Hey, Dave, look at what this damned thing is doing in the north.”) It fed his rage to watch, and for reasons he would never understand, it gave him a twisted pleasure to hate so fiercely.

When finally the cloud grew dormant, pieces of it broke off and began to drift away, as if there were no gravity near the planet to hold on to them. The skies began to clear.

The cities were charred and wrecked, wreathed in black smoke. Ava was in tears. Most of the others were in a state of shock. The devastation was more complete than anything they had imagined.