A noontime entertainment. A darting flitter craft was beginning a cloud sculpture. The pilot chopped, pruned, extruded and sliced the taffy-white cumulus. A being emerged: serpentine tail, exaggerated fins, knotted balls of cotton for feet. The event was admirably timed—as the flitter shepherded the remaining puffs into place, to shape the snouted face, the eyes turned ominously dark. The eyeballs expanded and purpled and suddenly lightning forked between them, giving the alabaster dragon a surge of life. In a moment a wall of thunderheads split the beast in two, sullen clouds churning. Claps of thunder rolled over the park. Above Los Angeles a hazy rain began.

When Mr. Ichino looked again at Nigel he could perceive from his new posture that some of the tension had drained away. In its place was Nigel’s familiar pensive enthusiasm.

“You learned more?” Mr. Ichino said.

“A lot,” Nigel said absently. “Or rather, a lot of negative results.”

“About Wasco?”

“Right. The Wasco event, as it’s called. Can’t label it a bomb because nobody dropped it. It was buried about a kilometer in bedrock. Must’ve come near on thirty megatons. A pure fusion burn.”

“I heard there was little radiation.”

“Surprisingly little, yes. Cleaner than any bomb we know of.”

“Not ours.”

“No, certainly not ours. The cover story is that a lot of experts think it was a human accident, but I never met anybody who buys that. No, it was alien. Triggered by the Marginis wreck at the same time that survey craft one oh five was getting snuffed.”

“But why? If the wreck thought it was being attacked…”

“Don’t look for order in any of this. It’s a malfunctioning ship, period. It nearly got that girl, then plugged one oh five and some standing order inside it made it touch off the Wasco explosion. The fusion device was there, probably stored in an arsenal or a base—look, it’s all a balls-up, a pack of guesses. We don’t know much for dead certain.”

“Aren’t the men working at the wreck in danger if they know so little of what caused this?”

“I suppose. Though the wreck has a blind side—the hill it’s on masks most of the sky in that direction. That’s how those three fellows got to the girl in time. They took a shuttle across Mare Crisium at low altitude, landed on the other face of the hill and simply walked around it. The wreck doesn’t fire at anything on the ground, apparently. So they carried her out, in shock but repairable.”

“They did not try to penetrate the invisible screen?” “No point. Leastwise, not then. Some physicists have taken a knock at it since—they say it’s high-frequency electromagnetic, with an incredible energy density—but they failed.”

“Ah.”

Nigel cast him a sidelong glance. Mr. Ichino smiled. Wind rippled the pepper tree and murmured through the park and brushed by them. “And where are you leading, Nigel?”

“That obvious, eh?” he said dryly.

“You know I am retiring. I cannot work on this riddle any longer.”

“I know, but—”

“You do not think you can talk me out of it, I hope?” “No, I wouldn’t be that thick. But you’re wrong about not taking part in all this.”

Mr. Ichino wrinkled his brow. “How?”

Nigel hunched forward eagerly. “I read the prelim study on the Wasco crater. It’s a mammoth hole and the land’s scraped clean in a seventy-five-kilometer radius. But there’s where the detective work ends. Whatever housed the fusion device is obliterated.”

“Of course. There is nothing to be learned there. The only possible research must be done on the moon.”

“Perhaps, perhaps,” Nigel said lightly. “But suppose there was something stored at Wasco. Why? Easier to salt stuff away on the moon.”

“Unless you were working on Earth.”

“Exactly. Now, we haven’t a clue how old that wreck is. It probably had some sort of camouflage going earlier so nobody picked it up on the Marginis search. But if the wreck has been there a longish time, there might have been ancient operations on Earth.”

“And you wish to look for traces of that.”

“Ah… yes.”

“Interesting.”

“It’s simply a matter of where you retire.”

Mr. Ichino gave a puzzled glance.

“Well, say you spend some time this winter in the north woods.” Nigel spread his hands and shrugged, his offhanded-and-reasonable gesture. “See if there is any history of unusual activities there.”

“It sounds outlandish.” “This is outlandish.”

“Do you honestly think this has any reasonable probability of success?”

“No. But we aren’t being reasonable. We’re guessing what’s near on to unguessable.”

“Nigel.” Mr. Ichino leaned forward from his position and touched Nigel’s wrist. The other man’s eyes were earnest, excited. There was something in this dynamic tension Mr. Ichino recognized in himself, as he had been decades before. Nigel was, after all, nine years his junior. “Nigel, I want to end with this. I do not feel at peace here.”

“If you tried you might get to work on the Marginis wreck.”

“No. Age, inexperience—no.”

“Right then, granted. But you can make a contribution by running down this nagging bit—there may be something to be learned up there. Some trace, a fragment—I don’t know.”

“NASA will uncover it.”

“Of that I’m by no means sure. And even if they did— can we trust them to pass it on? With the New Sons so powerful now?”

“I see.” Mr. Ichino’s face became absentmindedly blank, concentrated. He licked his lips. He gazed around the tranquil park where in the distance the air rippled with summer heat. He noticed that Nigel was wisely giving him time to let the words and arguments sink in. Still, Mr. Ichino fretted uncertainly. He studied the people lounging and eating around them, dotted on the emerald lawn at the intervals decreed by privacy. Office workers, newspaper readers, derelicts, welfare stringers, the elderly, students, the dying, all sopping up the forgiving sun. Down the flagstone path came businessmen, always in pairs, always talking, earnestly not here and earnestly going someplace else. Commonplace. Ordinary. It felt so odd to speak of the alien in the midst of this relentlessly average world. He wondered if Nigel was more subtle than he seemed; something in this atmosphere made it possible for Mr. Ichino to change his mind.

“Very well,” he said. “I will do it.”

Nigel smiled and at the corners of his upturned mouth there seeped out a boundless, childlike glee; a seasoned anticipation; a regained momentum.

Nigel squinted at the faxscreen memo: