The third night of the Marco Four’s landfall on the moonless Altarian planet was a repetition of the two before it, a nine-hour intermission of drowsy, pastoral peace. Navigator Arthur Farrell--it was his turn to stand watch--was sitting at an open-side port with a magnoscanner ready; but in spite of his vigilance he had not exposed a film when the inevitable pre-dawn rainbow began to shimmer over the eastern ocean.

Sunrise brought him alert with a jerk, frowning at sight of two pinkish, bipedal Arzian fishermen posted on the tiny coral islet a quarter-mile offshore, their blank triangular faces turned stolidly toward the beach.

“They’re at it again,” Farrell called, and dropped to the mossy turf outside. “Roll out on the double! I’m going to magnofilm this!”

Stryker and Gibson came out of their sleeping cubicles reluctantly, belting on the loose shorts which all three wore in the balmy Arzian climate. Stryker blinked and yawned as he let himself through the port, his fringe of white hair tousled and his naked paunch sweating. He looked, Farrell thought for the thousandth time, more like a retired cook than like the veteran commander of a Terran Colonies expedition.

Gibson followed, stretching his powerfully-muscled body like a wrestler to throw off the effects of sleep. Gibson was linguist-ethnologist of the crew, a blocky man in his early thirties with thick black hair and heavy brows that shaded a square, humorless face.

“Any sign of the squids yet?” he asked.

“They won’t show up until the dragons come,” Farrell said. He adjusted the light filter of the magnoscanner and scowled at Stryker. “Lee, I wish you’d let me break up the show this time with a dis-beam. This butchery gets on my nerves.”

Stryker shielded his eyes with his hands against the glare of sun on water. “You know I can’t do that, Arthur. These Arzians may turn out to be Fifth Order beings or higher, and under Terran Regulations our tampering with what may be a basic culture-pattern would amount to armed invasion. We’ll have to crack that cackle-and-grunt language of theirs and learn something of their mores before we can interfere.”

Farrell turned an irritable stare on the incurious group of Arzians gathering, nets and fishing spears in hand, at the edge of the sheltering bramble forest.

“What stumps me is their motivation,” he said. “Why do the fools go out to that islet every night, when they must know damned well what will happen next morning?”

Gibson answered him with an older problem, his square face puzzled. “For that matter, what became of the city I saw when we came in through the stratosphere? It must be a tremendous thing, yet we’ve searched the entire globe in the scouter and found nothing but water and a scattering of little islands like this one, all covered with bramble. It wasn’t a city these pink fishers could have built, either. The architecture was beyond them by a million years.”

Stryker and Farrell traded baffled looks. The city had become something of a fixation with Gibson, and his dogged insistence--coupled with an irritating habit of being right--had worn their patience thin.

“There never was a city here, Gib,” Stryker said. “You dozed off while we were making planetfall, that’s all.”

Gibson stiffened resentfully, but Farrell’s voice cut his protest short. “Get set! Here they come!”

Out of the morning rainbow dropped a swarm of winged lizards, twenty feet in length and a glistening chlorophyll green in the early light. They stooped like hawks upon the islet offshore, burying the two Arzian fishers instantly under their snapping, threshing bodies. Then around the outcrop the sea boiled whitely, churned to foam by a sudden uprushing of black, octopoid shapes.

“The squids,” Stryker grunted. “Right on schedule. Two seconds too late, as usual, to stop the slaughter.”

A barrage of barbed tentacles lashed out of the foam and drove into the melee of winged lizards. The lizards took the air at once, leaving behind three of their number who disappeared under the surface like harpooned seals. No trace remained of the two Arzian natives.

“A neat example of dog eat dog,” Farrell said, snapping off the magnoscanner. “Do any of those beauties look like city-builders, Gib?”

Chattering pink natives straggled past from the shelter of the thorn forest, ignoring the Earthmen, and lined the casting ledges along the beach to begin their day’s fishing.

“Nothing we’ve seen yet could have built that city,” Gibson said stubbornly. “But it’s here somewhere, and I’m going to find it. Will either of you be using the scouter today?”

Stryker threw up his hands. “I’ve a mountain of data to collate, and Arthur is off duty after standing watch last night. Help yourself, but you won’t find anything.”

The scouter was a speeding dot on the horizon when Farrell crawled into his sleeping cubicle a short time later, leaving Stryker to mutter over his litter of notes. Sleep did not come to him at once; a vague sense of something overlooked prodded irritatingly at the back of his consciousness, but it was not until drowsiness had finally overtaken him that the discrepancy assumed definite form.

He recalled then that on the first day of the Marco’s planetfall one of the pink fishers had fallen from a casting ledge into the water, and had all but drowned before his fellows pulled him out with extended spear-shafts. Which meant that the fishers could not swim, else some would surely have gone in after him.

And the Marco’s crew had explored Arz exhaustively without finding any slightest trace of boats or of boat landings. The train of association completed itself with automatic logic, almost rousing Farrell out of his doze.

“I’ll be damned,” he muttered. “No boats, and they don’t swim. _Then how the devil do they get out to that islet?_”

He fell asleep with the paradox unresolved.

Stryker was still humped over his records when Farrell came out of his cubicle and broke a packaged meal from the food locker. The visicom over the control board hummed softly, its screen blank on open channel.

“Gibson found his lost city yet?” Farrell asked, and grinned when Stryker snorted.

“He’s scouring the daylight side now,” Stryker said. “Arthur, I’m going to ground Gib tomorrow, much as I dislike giving him a direct order. He’s got that phantom city on the brain, and he lacks the imagination to understand how dangerous to our assignment an obsession of that sort can be.”

Farrell shrugged. “I’d agree with you offhand if it weren’t for Gib’s bullheaded habit of being right. I hope he finds it soon, if it’s here. I’ll probably be standing his watch until he’s satisfied.”

Stryker looked relieved. “Would you mind taking it tonight? I’m completely bushed after today’s logging.”

Farrell waved a hand and took up his magnoscanner. It was dark outside already, the close, soft night of a moonless tropical world whose moist atmosphere absorbed even starlight. He dragged a chair to the open port and packed his pipe, settling himself comfortably while Stryker mixed a nightcap before turning in.

Later he remembered that Stryker dissolved a tablet in his glass, but at the moment it meant nothing. In a matter of minutes the older man’s snoring drifted to him, a sound faintly irritating against the velvety hush outside.

Farrell lit his pipe and turned to the inconsistencies he had uncovered. The Arzians did not swim, and without boats...

It occurred to him then that there had been two of the pink fishers on the islet each morning, and the coincidence made him sit up suddenly, startled. Why two? Why not three or four, or only one?

He stepped out through the open lock and paced restlessly up and down on the springy turf, feeling the ocean breeze soft on his face. Three days of dull routine logwork had built up a need for physical action that chafed his temper; he was intrigued and at the same time annoyed by the enigmatic relation that linked the Arzian fishers to the dragons and squids, and his desire to understand that relation was aggravated by the knowledge that Arz could be a perfect world for Terran colonization. That is, he thought wryly, if Terran colonists could stomach the weird custom pursued by its natives of committing suicide in pairs.

He went over again the improbable drama of the past three mornings, and found it not too unnatural until he came to the motivation and the means of transportation that placed the Arzians in pairs on the islet, when his whole fabric of speculation fell into a tangled snarl of inconsistencies. He gave it up finally; how could any Earthman rationalize the outlandish compulsions that actuated so alien a race?

He went inside again, and the sound of Stryker’s muffled snoring fanned his restlessness. He made his decision abruptly, laying aside the magnoscanner for a hand-flash and a pocket-sized audicom unit which he clipped to the belt of his shorts.