The cool green disk of Alphard Six on the screen was infinitely welcome after the arid desolation and stinking swamplands of the inner planets, an airy jewel of a world that might have been designed specifically for the hard-earned month of rest ahead. Navigator Farrell, youngest and certainly most impulsive of the three-man Terran Reclamations crew, would have set the Marco Four down at once but for the greater caution of Stryker, nominally captain of the group, and of Gibson, engineer, and linguist. Xavier, the ship’s little mechanical, had--as was usual and proper--no voice in the matter.

“Reconnaissance spiral first, Arthur,” Stryker said firmly. He chuckled at Farrell’s instant scowl, his little eyes twinkling and his naked paunch quaking over the belt of his shipboard shorts. “Chapter One, Subsection Five, Paragraph Twenty-seven: No planetfall on an unreclaimed world shall be deemed safe without proper--“

Farrell, as Stryker had expected, interrupted with characteristic impatience. “Do you sleep with that damned Reclamations Handbook, Lee? Alphard Six isn’t an unreclaimed world--it was never colonized before the Hymenop invasion back in 3025, so why should it be inhabited now?”

Gibson, who for four hours had not looked up from his interminable chess game with Xavier, paused with a beleaguered knight in one blunt brown hand.

“No point in taking chances,” Gibson said in his neutral baritone. He shrugged thick bare shoulders, his humorless black-browed face unmoved, when Farrell included him in his scowl. “We’re two hundred twenty-six light-years from Sol, at the old limits of Terran expansion, and there’s no knowing what we may turn up here. Alphard’s was one of the first systems the Bees took over. It must have been one of the last to be abandoned when they pulled back to 70 Ophiuchi.”

“And I think you live for the day,” Farrell said acidly, “when we’ll stumble across a functioning dome of live, buzzing Hymenops. Damn it, Gib, the Bees pulled out a hundred years ago, before you and I were born--neither of us ever saw a Hymenop, and never will!”

“But I saw them,” Stryker said. “I fought them for the better part of the century they were here, and I learned there’s no predicting nor understanding them. We never knew why they came nor why they gave up and left. How can we know whether they’d leave a rear-guard or booby trap here?”

He put a paternal hand on Farrell’s shoulder, understanding the younger man’s eagerness and knowing that their close-knit team would have been the more poorly balanced without it.

“Gib’s right,” he said. He nearly added as usual. “We’re on rest leave at the moment, yes, but our mission is still to find Terran colonies enslaved and abandoned by the Bees, not to risk our necks and a valuable Reorientations ship by landing blind on an unobserved planet. We’re too close already. Cut in your shields and find a reconnaissance spiral, will you?”

Grumbling, Farrell punched coordinates on the Ringwave board that lifted the Marco Four out of her descent and restored the bluish enveloping haze of her repellors.

Stryker’s caution was justified on the instant. The speeding streamlined shape that had flashed up unobserved from below swerved sharply and exploded in a cataclysmic blaze of atomic fire that rocked the ship wildly and flung the three men to the floor in a jangling roar of alarms.

“So the Handbook tacticians knew what they were about,” Stryker said minutes later. Deliberately he adopted the smug tone best calculated to sting Farrell out of his first self-reproach, and grinned when the navigator bristled defensively. “Some of their enjoinders seem a little stuffy and obvious at times, but they’re eminently sensible.”

When Farrell refused to be baited Stryker turned to Gibson, who was busily assessing the damage done to the ship’s more fragile equipment, and to Xavier, who searched the planet’s surface with the ship’s magnoscanner. The Marco Four, Ringwave generators humming gently, hung at the moment just inside the orbit of Alphard Six’s single dun-colored moon.

Gibson put down a test meter with an air of finality.

“Nothing damaged but the Zero Interval Transfer computer. I can realign that in a couple of hours, but it’ll have to be done before we hit Transfer again.”

Stryker looked dubious. “What if the issue is forced before the ZIT unit is repaired? Suppose they come up after us?”

“I doubt that they can. Any installation crudely enough equipped to trust in guided missiles is hardly likely to have developed efficient space craft.”

Stryker was not reassured.

“That torpedo of theirs was deadly enough,” he said. “And its nature reflects the nature of the people who made it. Any race vicious enough to use atomic charges is too dangerous to trifle with.” Worry made comical creases in his fat, good-humored face. “We’ll have to find out who they are and why they’re here, you know.”

“They can’t be Hymenops,” Gibson said promptly. “First, because the Bees pinned their faith on Ringwave energy fields, as we did, rather than on missiles. Second, because there’s no dome on Six.”

“There were three empty domes on Five, which is a desert planet,” Farrell pointed out. “Why didn’t they settle Six? It’s a more habitable world.”

Gibson shrugged. “I know the Bees always erected domes on every planet they colonized, Arthur, but precedent is a fallible tool. And it’s even more firmly established that there’s no possibility of our rationalizing the motivations of a culture as alien as the Hymenops’--we’ve been over that argument a hundred times on other reclaimed worlds.”

“But this was never an unreclaimed world,” Farrell said with the faint malice of one too recently caught in the wrong. “Alphard Six was surveyed and seeded with Terran bacteria around the year 3000, but the Bees invaded before we could colonize. And that means we’ll have to rule out any resurgent colonial group down there, because Six never had a colony in the beginning.”

“The Bees have been gone for over a hundred years,” Stryker said. “Colonists might have migrated from another Terran-occupied planet.”

Gibson disagreed.

“We’ve touched at every inhabited world in this sector, Lee, and not one surviving colony has developed space travel on its own. The Hymenops had a hundred years to condition their human slaves to ignorance of everything beyond their immediate environment--the motives behind that conditioning usually escape us, but that’s beside the point--and they did a thorough job of it. The colonists have had no more than a century of freedom since the Bees pulled out, and four generations simply isn’t enough time for any subjugated culture to climb from slavery to interstellar flight.”

Stryker made a padding turn about the control room, tugging unhappily at the scanty fringe of hair the years had left him.

“If they’re neither Hymenops nor resurgent colonists,” he said, “then there’s only one choice remaining--they’re aliens from a system we haven’t reached yet, beyond the old sphere of Terran exploration. We always assumed that we’d find other races out here someday, and that they’d be as different from us in form and motivation as the Hymenops. Why not now?”

Gibson said seriously, “Not probable, Lee. The same objection that rules out the Bees applies to any trans-Alphardian culture--they’d have to be beyond the atomic fission stage, else they’d never have attempted interstellar flight. The Ringwave with its Zero Interval Transfer principle and instantaneous communications applications is the only answer to long-range travel, and if they’d had that they wouldn’t have bothered with atomics.”

Stryker turned on him almost angrily. “If they’re not Hymenops or humans or aliens, then what in God’s name are they?”

“Aye, there’s the rub,” Farrell said, quoting a passage whose aptness had somehow seen it through a dozen reorganizations of insular tongue and a final translation to universal Terran. “If they’re none of those three, we’ve only one conclusion left. There’s no one down there at all--we’re victims of the first joint hallucination in psychiatric history.”

Stryker threw up his hands in surrender. “We can’t identify them by theorizing, and that brings us down to the business of first-hand investigation. Who’s going to bell the cat this time?”

“I’d like to go,” Gibson said at once. “The ZIT computer can wait.”

Stryker vetoed his offer as promptly. “No, the ZIT comes first. We may have to run for it, and we can’t set up a Transfer jump without the computer. It’s got to be me or Arthur.”

Farrell felt the familiar chill of uneasiness that inevitably preceded this moment of decision. He was not lacking in courage, else the circumstances under which he had worked for the past ten years--the sometimes perilous, sometimes downright charnel conditions left by the fleeing Hymenop conquerors--would have broken him long ago. But that same hard experience had honed rather than blunted the edge of his imagination, and the prospect of a close-quarters stalking of an unknown and patently hostile force was anything but attractive.

“You two did the field work on the last location,” he said. “It’s high time I took my turn--and God knows I’d go mad if I had to stay inship and listen to Lee memorizing his Handbook subsections or to Gib practicing dead languages with Xavier.”

Stryker laughed for the first time since the explosion that had so nearly wrecked the Marco Four.

“Good enough. Though it wouldn’t be more diverting to listen for hours to you improvising enharmonic variations on the Lament for Old Terra with your accordion.”

Gibson, characteristically, had a refinement to offer.

“They’ll be alerted down there for a reconnaissance sally,” he said. “Why not let Xavier take the scouter down for overt diversion, and drop Arthur off in the helihopper for a low-level check?”

Stryker looked at Farrell. “All right, Arthur?”

“Good enough,” Farrell said. And to Xavier, who had not moved from his post at the magnoscanner: “How does it look, Xav? Have you pinned down their base yet?”

The mechanical answered him in a voice as smooth and clear--and as inflectionless--as a ‘cello note. “The planet seems uninhabited except for a large island some three hundred miles in diameter. There are twenty-seven small agrarian hamlets surrounded by cultivated fields. There is one city of perhaps a thousand buildings with a central square. In the square rests a grounded spaceship of approximately ten times the bulk of the Marco Four.”

They crowded about the vision screen, jostling Xavier’s jointed gray shape in their interest. The central city lay in minutest detail before them, the battered hulk of the grounded ship glinting rustily in the late afternoon sunlight. Streets radiated away from the square in orderly succession, the whole so clearly depicted that they could see the throngs of people surging up and down, tiny foreshortened faces turned toward the sky.

“At least they’re human,” Farrell said. Relief replaced in some measure his earlier uneasiness. “Which means that they’re Terran, and can be dealt with according to Reclamations routine. Is that hulk spaceworthy, Xav?”

Xavier’s mellow drone assumed the convention vibrato that indicated stark puzzlement. “Its breached hull makes the ship incapable of flight. Apparently it is used only to supply power to the outlying hamlets.”

The mechanical put a flexible gray finger upon an indicator graph derived from a composite section of detector meters. “The power transmitted seems to be gross electric current conveyed by metallic cables. It is generated through a crudely governed process of continuous atomic fission.”

Farrell, himself appalled by the information, still found himself able to chuckle at Stryker’s bellow of consternation.

“Continuous fission? Good God, only madmen would deliberately run a risk like that!”

Farrell prodded him with cheerful malice. “Why say mad men? Maybe they’re humanoid aliens who thrive on hard radiation and look on the danger of being blown to hell in the middle of the night as a satisfactory risk.”

“They’re not alien,” Gibson said positively. “Their architecture is Terran, and so is their ship. The ship is incredibly primitive, though; those batteries of tubes at either end--”

“Are thrust reaction jets,” Stryker finished in an awed voice. “Primitive isn’t the word, Gib--the thing is prehistoric! Rocket propulsion hasn’t been used in spacecraft since--how long, Xav?”

Xavier supplied the information with mechanical infallibility. “Since the year 2100 when the Ringwave propulsion-communication principle was discovered. That principle has served men since.”

Farrell stared in blank disbelief at the anomalous craft on the screen. Primitive, as Stryker had said, was not the word for it: clumsily ovoid, studded with torpedo domes and turrets and bristling at either end with propulsion tubes, it lay at the center of its square like a rusted relic of a past largely destroyed and all but forgotten. What a magnificent disregard its builders must have had, he thought, for their lives and the genetic purity of their posterity! The sullen atomic fires banked in that oxidizing hulk--

Stryker said plaintively, “If you’re right, Gib, then we’re more in the dark than ever. How could a Terran-built ship eleven hundred years old get here?”

Gibson, absorbed in his chess-player’s contemplation of alternatives, seemed hardly to hear him.

“Logic or not-logic,” Gibson said. “If it’s a Terran artifact, we can discover the reason for its presence. If not--”

“Any problem posed by one group of human beings,” Stryker quoted his Handbook, “can be resolved by any other group, regardless of ideology or conditioning, because the basic perceptive abilities of both must be the same through identical heredity.”

“If it’s an imitation, and this is another Hymenop experiment in condition ecology, then we’re stumped to begin with,” Gibson finished. “Because we’re not equipped to evaluate the psychology of alien motivation. We’ve got to determine first which case applies here.”

He waited for Farrell’s expected irony, and when the navigator forestalled him by remaining grimly quiet, continued.

“The obvious premise is that a Terran ship must have been built by Terrans. Question: Was it flown here, or built here?”

“It couldn’t have been built here,” Stryker said. “Alphard Six was surveyed just before the Bees took over in 3025, and there was nothing of the sort here then. It couldn’t have been built during the two and a quarter centuries since; it’s obviously much older than that. It was flown here.”

“We progress,” Farrell said dryly. “Now if you’ll tell us how, we’re ready to move.”