"I know you can do wonders with them electroscopes of yours, Cap'n Future," Ezra scoffed. "But plenty of ships call at Venus all the time. How in space can you spot the Comet's trail among 'em all?"

  "The Comet," Curt reminded, "is a unique ship. Its cyclotrons produce an atomic discharge unlike any other. We'll know its ionized rocket-trail, if we find it."

  "Hope you're right," Ezra said gloomily. "I'm goin' to see if we can't pump up a little more speed. Space knows we'll need it." He limped off along the corridors. They heard his sharp voice exhorting the crew. "Rev those cycs up, you loafers! We're crawlin'."

  Curt Newton prepared to set up his portable electroscopic finder in the bridge of the cruiser. The Brain glided ahead. Joan lingered beside Curt.

  "You're really glad I came along, aren't you?" she asked him.

  "Of course, Joan," Curt replied blandly. "You're a first-class secret agent and you may be a lot of help to us."

  "I'm not talking about that and you know it!" she cried exasperatedly. "I might as well use my feminine wiles on Grag."

  Grag was plucking Curt's arm.

  "Do you really think they would kill Otho when they captured the Comet?" he asked.

  "I hope not," Captain Future answered soberly. "Otho's pretty hard to kill, anyway. I wouldn't worry about him, Grag."

  "Worry about him?" Grag boomed. "The only thing I'm worried about is that maybe he escaped!"

  He clanked away indignantly. Curt looked after him.

  "Poor old Grag, he's worried sick about Otho, and doesn't want anyone to know it."

  Hour followed hour as the fast cruiser flashed on toward Venus. The steady broom-boom of the cyclotrons and the roar of the rockets never faltered. The white speck of the cloudy planet grew slowly in size. Captain Future and Simon constantly checked and rechecked with the electroscope. Only the two greatest masters of science in the System could have detected that faint, impalpable trail of ionized atoms which they were following.

  "There are two trails, lad," Simon had reported. "One is the distinctive rocket-trail of the Comet, the other that of an ordinary ship."

  Curt nodded. "The ship the thieves came to the Moon in, of course. It's accompanying the Comet now. That's a break for us. They've had to hold down the Comet to the other craft's maximum speed."

  AS VENUS finally broadened out in full planetary splendor before them, Captain Future never left the electroscope. They were now crossing the rocket-trails left by other ships in passing, and he had to use all his powers of concentration to keep onto the Comet's distinctive spoor.

  "They headed for the southern hemisphere," Curt muttered to the others in the bridge. "That's where their base must be hidden."

  "It's the least inhabited part of Venus, so it'd be the likeliest spot for a secret hideout," Ezra Gurney agreed.

  Down into the cloudy atmosphere of the planet they dropped, in the southern hemisphere. Here the rocket-trail ended. Though an ionized rocket-discharge will remain constant a long time in space, it will not do so in an atmosphere, for the currents soon sweep it away.

  "From here on, we just hunt," Curt said grimly. "Drop down to low altitude and start sweeping over the surface in a widening spiral. If my calculations are correct, we're over the Great South Marsh."

  "There can't be no secret base in that hole!" Ezra blurted. "Why, there ain't even enough solid ground in it for a ship to land on."

  They dropped through the last cloud-layer into the clear lower atmosphere. The Great South Marsh lay beneath them. Giant green reeds and tangled, snaky vines choked the spaces between the larger swamp-trees. So dense was the vegetation that it completely hid the semi-liquid muck beneath. Queer reptilian birds flew above the foliage roof, uttering harsh screams.

  "There ain't nothin' in this mess for a thousand miles," Ezra grunted. "Even the Venusians are afraid to go into it."

  "That's just why it's a good hideout," Curt declared, scanning the horizons. "Keep watching for a ship or solid land."

  For two hours the Patrol ship cruised in widening spirals over the vast morass. The cloudy sky above was beginning to grow dark. The night fog was rising from the swamp in thickening white mists. The Brain's keen lens-eyes, straining through the gathering darkness, descried something.

  "There, lad — to the west!"

  Curt peered quickly. He glimpsed something that looked like a big, flat, square metal platform, floating on the marsh. Half a dozen space ships were parked upon it.

  "Descend at once before they see us!" he ordered sharply. "We daren't approach in this cruiser. They'd use the same mysterious weapon on us that they used on the Comet and the Rocketeers' ships."

  "Then what're we goin' to do?" Ezra asked.

  "We'll land here and a few of us can get through the marsh to that base," Curt explained. "We can slip in secretly and find Otho and the Comet. Then we'll jump these raiders before they can use the secret weapon."

  The Patrol cruiser dropped in the gathering night until its keel crushed the vegetation and began sinking into the muck.

  "You'll have to keep the keel-jets going to prevent sinking," Curt said. "All right, Ezra. You, Grag, Simon and I will go."

  But when they reached the door, Joan Randall was with them.

  "Do you think I'm going to miss the fun?" she demanded resentfully.

  "This marsh is no picnic," Curt rapped. "You've seen Venusian marsh tigers. The marsh men here are worse."

  "I've met lots of Venusian swamp men," scoffed Joan.

  "Swamp men are different," Curt stated. "They're just ordinary Venusian humans who live in some of the swamps. But marsh men are a different species from swamp men. They're an indigenous, amphibious race. They are fierce and hate anyone who intrudes into their great marshes."

  Joan shrugged calmly. "I think I'd like to see some of them. They sound sort of intriguing."

  "Intriguing?" Curt repeated in amazement. "I give up. Come on, and don't let yourself sink in this muck or you're through."

  They plunged down into the sticky marsh, sinking to their knees. Curt Newton led the way, using a broad-bladed swamper's knife to hack a path through the dense vegetation. Joan trudged manfully, while Ezra swore at the blood-flies viciously attacking them. Grag wallowed on with difficulty, but the Brain glided easily on his beams beside Curt.

  The darkness was misty, warm and oppressive, heavy with rank swamp smells and flower fragrances. The hum of huge insects, the slap of hanging vines and the suck of their feet in the muck were occasionally drowned out by the distant, appalling screech of a marsh tiger. Curt suddenly halted. They heard a confused swimming sound, a vague rippling swashing in the muck.

  "Marsh men!" Curt whispered. "I think they're surrounding us!"

  Chapter 5: Oog Redeems Himself

  OTHO was still chuckling as he left Captain Future, Grag and Simon in the Moon-laboratory and made his way to the Comer. "Oog, we out-talked Grag that time," he told the queer little pet who was trotting beside him.

  The Comet was kept in an underground hangar near the Moon-home. Otho entered the compact, teardrop-shaped vessel with his pet, closed the door and strode forward through the laboratory-cabin to the control room. He took the pilot chair and touched the cyclotron switches and throttles. Its keel-tubes jetting fire, the Comet rose toward the roof of the hangar. The roof slid aside automatically. The streamlined ship rose above the glaring surface of the Moon and then zoomed westward. Otho put on his space-suit, to be ready for his work in the lunar chasms.

  "Am I glad to get out a little!" Otho breathed. "If I'd been cooped up much longer, I'd have turned into an oyster."

  Oog heard him. The fat little meteor-mimic instantly shifted his body cells and became a perfect imitation of a giant Neptunian oyster.

  "No, no, Oog, I didn't mean for you to imitate an oyster," Otho said impatiently. "You're too quick on the trigger. Snap out of it."

  Oog returned to normal. Meanwhile the little ship was zipping at high speed around toward the other side of the Moon. Otho loved to get out alone. The android, beneath his devil-may-care recklessness and gaiety, had a sensitive, brooding mind. He keenly felt the fact that he was an artificial man. He liked to adventure by himself, imagining himself a human being.

  He was half around the Moon, traveling at high altitude, when the televisor beside him buzzed sharply. Curt's voice crackled from it.

  "Otho, the chief calling! Turn around and blast back here full speed. The President is calling us."

  Otho stiffened with excitement. A glance up at the green sphere of Earth showed that a tiny light was blinking at its North Pole.

  "That means trouble ahead!" he cried exultantly. "I'll be right back — " At that moment he felt a movement inside the Comet. He turned. There seemed to be nobody but himself in the ship, yet he knew he was not alone. "Say, something's happening! I —"

  Before he could say more, invisible forces seized him. Everything became a blur as he was whirled out of the pilot chair with inconceivable rapidity. His senses blanked out.

  When he came to himself, he was lying on the floor of the Comet. His space-suit helmet was off, and little Oog was worriedly pawing his face. Otho found he was tightly trussed by flexible metal bonds.

  "What in the name of ten thousand imps!" swore the enraged android. "Who —"

  His voice froze in amazement as he squirmed around and got a full view of the interior of the ship. The Comet was blasting through space at high speed. In its pilot chair now sat an amazing figure, and there was another beside him. They were machines that looked vaguely like men, mere open skeletons of metal girders crowded with complex, whirring mechanical organs. They had girder arms and legs, and their heads were square metal boxes with big glass visi-plates for eyes.

  Anyone else might have been too stupefied for speech at finding himself the helpless prisoner of two fearsome machine men, but not Otho. The android was not afraid of man or beast.

  "What the devil does this mean?" he yelled.

  The machine men paid him no attention. One of them was tuning the Comet's televisor to a certain wave. Then the creature spoke into it.

  "This is Six reporting," he said in a humming voice. "We captured the Comet, but only one of the Futuremen was in it. What shall we do?"

  Otho heard a deep bass voice answer. He could not see the televisor screen and did not know who was talking.

  "You have blundered, Six, in not securing the other Futuremen also," it stated. "But don't go back for them now. It would be too dangerous. Bring the Comet and your prisoner to Venus Base as planned. Wait till I signal that the coast is clear before coming on to Main Base."

  OTHO heard the machine man who called himself "Six" snap off the televisor before opening the Comet's throttles. The ship blasted through space, its cyclotrons droning. Otho glimpsed another ship — a Cruh-Cholo Twenty-four — accompanying them in space. He guessed these queer machine men had boarded from the other ship. The android squirmed and cursed and made futile efforts to break his bonds. The flexible metal bands were unbreakable. Meanwhile the two ships were flying on at mounting speed, heading for distant Venus.

  "What a pickle I've got myself into!" Otho muttered. "These freaks capturing me — Grag will laugh himself sick. Oh, well!"

  And Otho philosophically fell asleep. There was nothing he could do till they reached Venus. He might as well get some rest.

  He awoke to find the Comet's bow-tubes blasting. The ship was decelerating as it dropped through a cloudy atmosphere. He knew they had reached Venus. He squirmed on the floor till he was able to look down through the window at the landscape below.

  "The Great South Marsh!" he gasped.

  Then he glimpsed a big square metal platform in the marsh. It floated on the muck, supported by vacuum caissons. There were low metal hangars and buildings on it, and a row of parked ships of various makes — Kalbers, Zamors, Cruh-Cholos, one or two Tarks. The Comet and the other craft landed beside these ships.

  The two machine men came back and lifted Otho in stiff girder-arms. Oog fled in fright into a corner, but Otho swore a streak of his best interplanetary profanity as they carried him out into the daylight. The machine men paid no attention. They carried him toward one of the low metal buildings.

  The raging android saw more than a score of other machine men stalking stiffly about the floating base, inspecting and servicing the ships. Then he was taken to a windowless little metal room, whose only ventilation came from a barred opening in the door. They dumped him inside.

  "Are you going to starve me to death, you unfinished mechanisms?" Otho yelped as they started to leave. "How about something to eat?"

  The machine man who bore the number "Six" on his metal skeleton turned toward the other.

  "One said that this prisoner was to be kept living. He must eat. Bring food from one of the ships."

  The other machine man who bore the number "Twenty-two" stalked out and returned with Jovian cured beef, a flat slab of Martian black bread, some Earth fruit. Otho guessed that the other ships had been captured, and that this food came from one of them. Apparently these creatures didn't eat.

  "Are you going to leave me all tied up like this?" he demanded furiously.

  Six stooped stiffly and unfastened the end of Otho's flexible metal bonds. Then the two machine men stalked out. The door was locked.

  "Remain outside this door on guard, Twenty-two," ordered Six.

  Otho rolled over and over until he slipped out of his loosened bonds. Then he leaped to his feet.

  "So far, so good," he muttered. "At least I talked them into untying me. Now let's see if there's any way out of this cursed hole."

  TEN minutes of inspection showed him there was none. The only exit was the locked door, outside which towered the mechanical guard.

  "What a mess!" Otho grumbled. "Locked up in this hole and the Comet taken. The chief will skin me alive for this. Who the devil are these freaks, anyway? Where'd they get all those ships?"

  He gave up wondering, sat down and ate the food, for Otho's synthetic tissues required nourishment. Though he preferred straight chemical solutions of the needed elements, he could eat ordinary food. He was gloomily gnawing the tough Martian bread when a sliding, rustling sound froze him. He looked up and felt cold at what he saw. A thick white snake with a blunt head was crawling through the barred opening in the door and into his prison cell.

  "A Venusian swamp adder!" Otho whispered.

  It was one of the most poisonous serpents in the System. Otho looked around for a weapon. There was none. He stood taut as a bowstring, watching the snake slide into the room. The serpent reached the floor and coiled up there. The thick mass of its coils seemed suddenly to run together, to form one solid mass. Then that mass spun in shape. In place of the pseudo-snake was a fat little animal with big, solemn eyes.

  "Oog!" Otho gasped — "You little devil! You came sniffing after me, eh, and imitated a swamp adder so you wouldn't be noticed?"

  He patted the little meteor-mimic, chuckling. Oog made a purring sound. He seemed content, now that he had found his master. Otho suddenly had an idea.

  "Oog, I believe you can help me get out of here!" he breathed.

  Otho waited until darkness came. The machine men outside did not seem to require sleep, but darkness would make his break easier. Otho picked up his little pet. He spoke in an emphatic whisper.

  "Oog, I want you to be an atom bomb. Remember the atom bombs we used to blast ores out with, on the Moon? Big, black cones, with a switch-fuse on the end of each one? Be one now!"

  Oog looked up worriedly. He seemed to understand that a new metamorphosis — was required of him. He made a visible effort. The tissues of his strange body flowed and spun and formed a new shape. He made himself a perfect imitation of Eek.

  "No, not that now," Otho whispered hastily. Oog bewilderedly came back to normal. "A bomb, Oog, an imitation of an atom bomb!"

  Oog imitated one thing after another, everything he had seen Otho handle in the past. He became a small telescope, a space-sextant, a big flagon of Jovian brandy, a televisor receiver. Then, when Otho was despairing, Oog flowed into an imitation of a conical atom bomb.

  "That's it, Oog!" the android said excitedly. "Now hold it!"

  Otho went to the door and called through the opening to the machine man on guard outside. The mechanical creature stalked forward. Otho held up his pseudo-bomb menacingly.

  "See this?" he hissed. "If you make a sound of alarm, I'll turn its switch. It will blow this whole base off Venus."

  The machine man stared. He might not have been influenced by a threat to himself, but this was a threat to ruin the base and plans of his master.

  "What do you want me to do?" he hummed after a moment.

  "Open this door!" Otho snapped. "Then walk with me to the Comet. Pretend I'm still your prisoner, if we meet any others."

  The machine man slowly unbarred the door. Otho exultantly stepped out, still threatening with the pseudo-bomb.

  "Now head for the Comet!" he hissed. "March, you metal skeleton!"

  Oog heard Otho say "skeleton." He changed at once from an imitation atom bomb to an imitation skeleton.

  INSTANTLY the machine man understood that he had been deceived. With a humming shout he leaped forward at Otho. Otho nimbly eluded the groping girder-arms and with a vicious shove sent the creature clattering to the metal floor.

  "You would have to do that, Oog!" he snarled.

  He grabbed up the scared pet and burst out of the building into the dusk. He saw the Comet, but it was a hundred yards away. Between him and the ship were other machine men, coming to answer the alarm.

  "Devils of space, we can't reach the ship now!" Otho groaned. "And we'll be captured again unless we get out of here fast."

  He turned and raced to the nearby edge of the floating metal base, the machine men pursuing with humming shouts. Otho dived off the edge of the metal platform. He writhed rapidly into the deepening darkness through the tangled vines and muck of the morass. Not Until he was so far that he could not hear the humming cries did he halt in a clump of fungi.