crumbled desolation of Terran slave barracks had been depressing enough. The inevitable scattering of empty domes abandoned a hundred years before by the Hymenop conquerors had completed a familiar and unpromising pattern, a workaday blueprint that differed from previous experience only in one significant detail: There was no shaggy, disoriented remnant of descendants from the original colonists.

The valley, a mile-wide crater sunk between thousand-foot cliffs, floored with straggling bramble thickets and grass flats pocked with stagnant pools and quaking slime-bogs, had been infinitely worse. The cryptic three-dimensional maze of bridges spanning the pit had made landing there a ticklish undertaking. Stryker and Farrell and Gibson, after a conference, had risked the descent only because the valley offered a last possible refuge for survivors.

Their first real hint of what lay ahead of them came when Xavier, the ship's mechanical, opened the personnel port against the heat and humid stink of the place.

"Another damned tropical pesthole," Farrell said, shucking off his comfortable shorts and donning booted coveralls for the preliminary survey. "The sooner we count heads—assuming there are any left to count—and get out of here, the better. The long-term Reorientation boys can have this one and welcome."

Stryker, characteristically, had laughed at his navigator's prompt disgust. Gibson, equally predictable in his way, had gathered his gear with precise efficiency, saying nothing.

"It's a routine soon finished," Stryker said. "There can't be more than a handful of survivors here, and in any case we're not required to do more than gather data from full-scale recolonization. Our main job is to prepare Reorientation if we can for whatever sort of slave-conditioning deviltry the Hymenops practiced on this particular world."

Farrell grunted sourly. "You love these repulsive little puzzles, don't you?"

Stryker grinned at him with good-natured malice. "Why not, Arthur? You can play the accordion and sketch for entertainment, and Gib has his star-maps and his chess sessions with Xavier. But for a fat old man, rejuvenated four times and nearing his fifth and final, what else is left except curiosity?"

He clipped a heat-gun and audicom pack to the belt of his bulging coveralls and clumped to the port to look outside. Roiling gray fog hovered there, diffusing the hot magenta point of Falak's sun to a liverish glare half-eclipsed by the crater's southern rim. Against the light, the spidery metal maze of foot-bridging stood out dimly, tracing a random criss-cross pattern that dwindled to invisibility in the mists.

"That network is a Hymenop experiment of some sort," Stryker said, peering. "It's not only a sample of alien engineering—and a thundering big one at that—but an object lesson on the weird workings of alien logic. If we could figure out what possessed the Bees to build such a maze here—"

"Then we'd be the first to solve the problem of alien psychology," Farrell finished acidly, aping the older man's ponderous enthusiasm. "Lee, you know we'd have to follow those hive-building fiends all the way to 70 Ophiuchi to find out what makes them tick. And twenty thousand light-years is a hell of a way to go out of curiosity, not to mention a dangerous one."

"But we'll go there some day," Stryker said positively. "We'll have to go because we can't ever be sure they won't try to repeat their invasion of two hundred years ago."

He tugged at the owlish tufts of hair over his ears, wrinkling his bald brow up at the enigmatic maze.

"We'll never feel safe again until the Bees are wiped out. I wonder if they know that. They never understood us, you know, just as we never understood them—they always seemed more interested in experimenting with slave ecology than in conquest for itself, and they never killed off their captive cultures when they pulled out for home. I wonder if their system of logic can postulate the idea of a