CHAPTER I
Von Zorn Is Perturbed

Whenever Von Zorn, chief of Nine Planets Films, ran into trouble he automatically started the televisors humming with calls for Anthony Quade. The televisors were humming now. In fact they were shrieking hysterically. Quade’s code number bellowed out through a startled and partially deafened Hollywood on the Moon.

Von Zorn, teetering on the edge of his chair behind the great glass-brick desk, was throwing a fit.

“You can’t do this to me!” he yelped into the transmitter, his scrubby mustache bristling with outrage. “I know you can hear me, Quade! It’s a matter of life and death! Quade!”

A covey of anxious secretaries winced involuntarily as he swung the chair around.

“Get Quade!” he screamed. “Bring me Quade! All you do is stand around with your mouths open. I—” He paused, the light of an unpleasant idea dawning across his face. He was grinning disagreeably as he switched the televisor to a private wavelength.

“I’ll fix him!” he muttered. “I’ll—oh, hello.” This to the face that flashed onto the screen before him. Rapidly Von Zorn spoke to the face. It nodded, smiling grimly.

Afterward Von Zorn leaned back and called for a drink.

“Nine Planets on the brink of ruin,” he growled into the tilted glass, “and Quade runs out on me. I’ll fire him! I’ll blackball him all over the System! But not till he does this job.”

Meanwhile Tony Quade, relaxing comfortably in a seat at the Lunar Bowl, listened to a distant orchestra in the depths of the crater crash into the opening strains of the Star Symphony. Under his coat a pocket televisor was buzzing shrill commands.

Quade chuckled and shifted his big-boned body more comfortably in the padded chair. Kathleen Gregg, beside him, smiled in the dimness and he told himself that she was prettier than ever.

It was to her credit that she loathed the title of “The System’s Sweetheart” which an enthusiastic publicity department had bestowed upon her. She was one of Nine Planets’ brightest stars and Tony Quade was in love with her.

“Hello, stupid,” he said lazily. “You look worried. Anything wrong?”

“I suppose you know what you’re doing,” Kathleen murmured. “Of course, Von Zorn’s only been calling you half an hour.”

The cries from the pocket televisor had been all too audible, Quade realized. He grinned largely and laid an arm along the back of her chair.

“Let him yell.”

“It must be important, Tony.”

“I,” said Quade, “am resting. Shooting Star Parade was hard work. I need a rest. Anyhow, it’s much too nice a night to listen to Von Zorn.”

“It is nice,” the girl agreed. She glanced around them. This was the topmost tier of the Lunar Bowl. At their feet the long rows of seats swept down endlessly to the central platform far below, where an orchestra sat in the changing play of varicolored searchlights.

Behind these uppermost seats stretched Hollywood on the Moon, the strangest city in the Solar System. The wonder of Hollywood on the Moon does not quickly fade, even to eyes that have seen it often. It is a garden metropolis on the far side of Earth’s satellite, in a gigantic valley bounded by the Great Rim.

Here the film studios had built their city, washed by an artificially created, germ-free atmosphere, anchored in the crater by electro-magnetic gravity fields maintained in the caverns below. Far distant, the Silver Spacesuit glowed with pale radiance, the broad, white-lit expanse of Lunar Boulevard stretching past it toward the Rim.

From somewhere above a beam of light shot suddenly downward full upon them. Blinded, Quade and Kathleen looked up, seeing nothing at all. Then, without any warning, Quade arose and floated starward.

Kathleen made a quick, involuntary snatch at his vanishing heels, missed, and cried distractedly.

“Tony!”

From somewhere above his voice spoke with annoyance.

“They’ve got a gravity beam on me. I could get loose, but I’d break my neck.” The sound trailed off into a distant murmur. “I’ll murder Von Zorn for this....”

Quade felt solid metal beneath his feet. The beam faded. Blinking, he looked around. This was the lower lock of a police ship. Black-clad officers were wheeling away the great anti-gravity lens. A man with a captain’s bars took his finger off the button that had closed the lock and looked at Quade speculatively.

“What’s the idea?” Quade demanded crossly.

“Sorry, sir. We’re looking for a Moonship stowaway. You answer his description.”

“My name’s Quade. I don’t suppose you’d even look at my credentials.”

The captain looked blank.

“Might be forged, you know. We can’t afford to take chances. If you’re Tony Quade, Mr. Von Zorn can identify you.”

“He will,” Quade said between his teeth. “Yeah—he will!”

Five minutes later they stood in Von Zorn’s office. The film executive looked up from a script and nodded coldly.

“Tell him who I am,” Quade said in a weary voice. “I’ve got a date.”

“It’s not as easy as that. You’re either Quade or a Moonship stowaway. If you’re Quade I’ve got to talk to you.”

“I’ve got a date. Also, I quit.”

Von Zorn ignored this.

“If you’re not Quade it means jail, doesn’t it?” He glanced at the captain, who nodded.

Quade thought it over. Of course he could get out of jail without much trouble, but not perhaps for some hours. Besides, he was beginning to wonder what mishap had occurred. It must be pretty serious.

“Okay,” he said. “I’m Quade. Now tell your stooge to rocket out of here.”

Von Zorn nodded with satisfaction, waved the captain away and pushed toward Quade a box of greenish, aromatic Lunar cigars. Quade pointedly lit one of his own cigarettes and sat down in a glass-and-leather chair.

“Shoot.”

But Von Zorn wasn’t anxious to begin. He took a cigar, bit the end off savagely, and applied flame. Finally he spoke.

“Udell’s dead.”

Quade was startled. He put down his cigarette.

“Poor old chap. How did it happen?”

“In the Asteroid Belt. A meteor smashed his ship. He was coming back here from Titan. A patrol ship just towed his boat in.”

Quade nodded. He had met Jacques Udell only a few times, but he’d liked the eccentric old fellow, who was somewhat of a genius in his own fashion. A scientist who had turned to film-making, he had once or twice created pictures that had amazed the System—like Dust, the saga of the nomad Martian tribes.

“All right.” Von Zorn punctuated his sentences with jabs of the cigar. “Get this, Tony. Last month Udell sent me a package and a letter. In the package was a can of film. I ran it off. He’d filmed the Zonals.”

“That’s been done before—for what it’s worth. They’re sub-humans, aren’t they? Not much story-value there.”

“They’re the queerest race in the system. Ever see one? Wait till you do—you won’t believe it! Udell worked some sort of miracle—he really got a story. The Zonals acted in it for him. Intelligently!”

“That doesn’t seem possible.”

“It isn’t. But Udell did it. He shot one reel and sent it to me with the scenario. It’s a good story. It’ll be a smash hit. I bought the pic on the strength of the first reel. Paid plenty for it. I’ve sent out advance blurbs and it’s too late to call them all back now.”

“Udell didn’t finish?”

Von Zorn shook his head.

“He was on his way back here for some reason or other, with two more reels finished, when a meteor cracked him up. The reels are spoiled, of course. Udell didn’t have sense enough to insulate ’em.”

Von Zorn snapped his cigar in two.

“I own the picture. I paid him for it. But he was the only man who knew how to make the Zonals work for the camera. See the catch, Tony?”

“You want me to finish the pic. A nice easy job. Why not fake the rest of it?”

“I don’t dare,” Von Zorn admitted frankly. “I’ve already blurbed this as the real thing. It’d raise too big a howl if we used robots. I can imagine what that Carlyle dame would do.”

Quade grinned maliciously.

“Catch-’em-Alive” Carlyle, interplanetary explorer extraordinary, was Von Zorn’s vulnerable point, his heel of Achilles.

“She’s suing me,” Von Zorn said, breathing audibly. “For libel. Says the Gerri Murri cartoons are libelous.”

“Well, aren’t they?” Quade asked. This animated cartoon series, depicting Gerry Carlyle as an inquisitive bug-eyed Venusian Murri, had proved immensely popular with everybody but Gerry. She had created a fair-sized riot in Froman’s Mercurian Theatre when she first recognized her counterpart on the screen.

“We won’t discuss that—that—” Von Zorn gulped and finished weakly, “that tomato. Do you want to see Udell’s film on the Zonals?”

“Might as well,” Quade agreed, getting up. “I may get some ideas about his method.”

“You’d better get some ideas,” Von Zorn said darkly, “or we’ll all be in the soup.”

CHAPTER II
Trip to Titan

The next morning Quade went to the spaceport to examine Udell’s wrecked ship, which had arrived in tow a few hours before. Von Zorn was with him and at the last moment Kathleen, scenting something interesting, attached herself to Quade’s elbow and would not be dislodged.

Quade was not entirely happy about her presence, because of a vague uneasiness he could not name. He had hunches like that occasionally. He felt one strongly now about the wrecked ship and the dangers that might lie dormant there.

“You see, silly, nothing’s wrong,” Kathleen said impatiently as they stood in the great torn hole that had been the ruined ship’s side. The vessel, a small, six-man job, was warped and twisted grotesquely by the impact of the meteor, which had ripped completely through the walls of the control room and emerged into space on the other side. The bodies had been removed, but nothing else was yet touched.

“All the same,” Quade told the girl uneasily, “I don’t like it. I wish you’d stay outside.”

“Ha!” Kathleen said in a sceptical voice and ducked her curly head under the torn wall to peer inside. “Nothing here. Don’t be such a sissy, Tony. What could possibly hurt me?”

“How can I tell? All I know is, wherever you go there’s trouble. Stand back now and let me take a look.”

But he found nothing. Even a careful search of the interior disclosed little to warrant that feeling that something more serious had happened here than a mere chance accident with a meteor. The only thing that puzzled him was the wreckage in the ship.

Bottles, instruments, gauges, seemed smashed more thoroughly than they should be, considering the impact of the meteor. Furniture was splintered, not only in the control room but in every other part of the vessel.

“I don’t get this,” Quade said slowly. “The meteor didn’t cause all this damage. It looks—” He hesitated. “It looks as though Udell and his men had gone on a spree. But there’s no sign of liquor on the ship.”

“Oxygen jag?” Von Zorn suggested.

Quade examined the tanks.

“No, it doesn’t look like it. They didn’t even use oxygen to try to save themselves. Look—they could have blocked off the control room with airtight panels and released oxygen. Or they might at least have got into their spacesuits. There must have been time for that. I’ve got a hunch—”

Von Zorn was examining the cans of film, the casings intact but the film itself spoiled by exposure.

“Eh?” he said. “You have a theory?”

“An idea, that’s all. If Udell and the navigator had been in their right minds, they needn’t have collided with the meteor. Look here—the automatic repulsors are smashed. That’s what caused the trouble.”

“In their right minds?” Von Zorn echoed slowly. “Space-cafard?”

“Hitting all of ’em? Hardly! Is a postmortem being done?”

Von Zorn nodded.

“The report ought to be ready by now if you want to check up.” He chewed his cigar savagely. “If only one man of the crew had lived! We’ve got a smash hit dumped on our laps and goodness knows if we can even film it.”

Kathleen put her head through a wrenched door-frame. She was a little pale.

“Really, Tony, it’s rather horrible. I hadn’t realized—I never saw a space wreck before.”

“Let’s get on the televisor,” Quade said decisively. “I’d like to check on the postmortems.”

He swung out through the half-fused port, and the others followed him into the Patrol office. A few minutes’ conversation with the authorities was all that was necessary when Von Zorn used his name. Then a gaunt face above a white jacket dawned on the screen. There were introductions.

“Did you find anything out of the ordinary?” Quade asked.

The reflected head shook negatively.

“Well, not what you’d expect, anyhow. The crash certainly killed them all, if that’s what you mean. No question of foul play. But—” He hesitated.

“But what?”

“Antibodies,” said the man reluctantly. “Something new. I can’t get any trace of a virus. Apparently some disease attacked the men. Their systems built up antibodies that I never encountered before. Something funny about the neural tissues, too. The cellular structure’s altered a little.”

Von Zorn thrust his head toward the screen.

“But what was it? That’s what we want to know. Were they conscious when they died?”

“I think not. My theory is that Udell and his crew were attacked by some disease native to Titan. Maybe the same disease that turned the Zonals into idiots.”

“I’ve got to go to Titan myself,” Quade said slowly. “Suppose we work there in spacesuits. Could a virus get through metal or glass?”

“I think you’d be safe. Mind you, that’s just my opinion. There’s such a thing as a filterable virus, you know. But, judging by the antibodies, I’d say there’d be no risk if you wore spacesuits constantly, outside your ship.”

“It won’t be easy,” Quade said, “but it’s better than infection.”

“We’ve taken tests of the wrecked ship,” the man in the screen told them. “No trace of any unusual disease-germ or virus. We’ve tested samples on protoplasmic cultures and got nothing but the ordinary bugs present everywhere. Sorry I can’t tell you more.”

“That’s okay,” Quade said. “Thanks.” He clicked off the televisor. “All right, then. We film Sons of Titan in spacesuits.”

Kathleen looked worried.

“I—I don’t like it, Tony. Do you have to—”

“Can’t leave a flicker like that unfinished,” Quade said. “I saw the reel Udell sent in. It’s magnificent theater. The tragedy of the Zonals—one of the biggest epics the System ever saw. They used to be highly civilized at one time, historians think, but something wrecked their brains.

“They’re decadent now, little better than animals. If I can film the rest of Sons of Titan, we’ll have something really big—Grass and Chang and Dust all rolled into one. If I can figure out how to make the Zonals act.

“They acted for Udell—magnificently. They lived their roles. And that’s what’s so mysterious, Kathleen. The Zonals aren’t really smart enough to come in out of the rain.”

“Could it have been faked?” the girl asked.

“No,” Von Zorn said decisively. “No question of robots. Udell made ace actors out of—of sub-idiots. The question is how?”

“Same way you did with that new crooner you’re starring, maybe,” Quade said rather sardonically. He was examining a slip of paper. “I picked this up in Udell’s ship—it’s a list of supplies he planned to get in Hollywood on the Moon. That’s probably why he came back from Titan—he ran out of some things he needed. Let’s see. Why did he want neo-curare?”

“What’s that?” Von Zorn asked.

“Derivative of curare. A poison that paralyzes the motor nerves. I didn’t know the Zonals had nerves.”

“Their neural structure’s atrophied, Tony. Mm-m. What else is on that list?”

“Cusconidin, Monsel’s Salt, sodium sulphoricinate, a baresthesiometer, lenses, filters, camera stuff—nothing special in the medical supplies Udell wanted. You’ve got to jazz up the pharmacy when you’re in space, anyhow. Your katabolism changes, and so on. Variant drugs—”

Von Zorn spoke abruptly.

“There was something about a degenerate race of Zonals that attacked Udell’s party, I think. An outlaw tribe. They had a high resistance to wounds; pretty invulnerable. Neo-curare’s a fast-working poison, isn’t it?

“Well—there’s your answer. Special ammunition against that particular tribe in case they attacked again. Udell probably intended to smear neo-curare on his ammunition.”

“Could be,” Quade said. He hesitated, thumbed a button and called Wolfe, his assistant, on the televisor. The youngster’s thin face and sharp blue eyes flashed into visibility on the screen.

“Hello, Tony. What’s up?”

“Got the camera-ship ready for the take-off?”

“Sure.”

“Well, here are some more supplies I want you to get. Photostat it.”

Quade pressed Udell’s list face down against the screen. After a moment Wolfe said, “Got it.”

Von Zorn seized the paper and began scanning it. Abruptly he emitted the anguished howl of a disemboweled wolf.

“Wait, Tony!” he cried desperately. “Not that! Venusian cochineal at a hundred dollars a pint, current quotation? Use surrogate red. It’s almost as good, and we don’t need—”

“I want everything—understand?” Quade said to the televisor. “Don’t leave out a thing.”

Stabbed in the budget, Von Zorn spun toward Kathleen Gregg.

“Next he’ll want diamond lenses and radium paint for technicolor effects, I suppose. Thirty-odd concentrated aqueous dyes—and they won’t even show on the celluloid!”

“The Zonals spend a lot of time underwater,” Quade said patiently. “And underwater camera work under alien conditions is tricky. You’ve got to experiment with the right dyes and special filters and lenses before you can get complete submarine clarity.”

“You’ve ordered enough concentrated dye to color the Pacific,” Von Zorn mourned. “Lake Erie at least. Why couldn’t Udell have found the right dye before he broke his contract?”

“Broke his contract?” Kathleen said wonderingly. “He didn’t—”

“He’s dead, isn’t he?” Von Zorn snarled and went off, as Quade rather suspected, to beat a child star—any child star who wasn’t big enough to be dangerous.

Quade got busy preparing for the expedition.

CHAPTER III
Location Site

Being the sixth satellite of Saturn, Titan is unpleasantly cold. It gets no heat from its major, since Saturn’s average temperature is 180° below zero F. But there are occasional volcanic areas, and in one of these, amid geysers and steaming lakes, is the only settlement of humans on Titan, New Macao, a roaring bordertown.

Most of the moon remains unexplored. There are continents and islands and iron-cold seas whose vast depth as well as the tidal pull of Saturn keep unfrozen. Maps on the satellite are mostly blank, with the outlines of the continents sketched in and a few radar-located landmarks indicated. Perhaps two dozen mining companies work some of the volcanic regions.

Equatoria, a continent as large as Africa, stretches from latitudes 45° north to 32° south. Udell had clearly marked on his chart the position of his Titan camp, a valley near the equator on the outskirts of Devil’s Range, a broad mountainous belt stretching across the equator for three hundred miles.

So Quade brought down his camera ship, a gleaming, transparent-nosed ovoid, in a five-mile-wide shallow basin clearly of volcanic origin. Steaming geyser plumes feathered up from the rocky floor. Towering cliffs of ice ringed the valley.

In the center a few shacks stood, but there was no sign of life. Though the atmosphere was breathable, Quade, remembering the mysterious virus, issued orders for continual wearing of spacesuits outside the ship. Moreover, he installed antiseptic baths in the spacelocks, in which every member of the crew had to dunk himself before reentering the vessel.

“We’re not near New Macao, are we?” Wolfe asked, a wistful gleam in his blue eyes as he peered through the transparent hull.

Quade grinned.

“Nope. We’re on the other side of the satellite. Why? Thirsty?”

“Kind of.”

“Better stay away from New Macao liquor,” Quade said solemnly. “Know what plasmosin is? It’s the fibre that holds the cells, of your body together. One shot of Martian absinthe, New Macao version, and the plasmosin lets go. You fall apart. Very bad.”

“Yeah?” Wolfe said, wide-eyed. “Gee, I’d like to try it.”

Quade chuckled and glanced at the instrument panel. “That’s funny,” he said suddenly.

“Eh?” Wolfe followed the other’s gaze. The needle of a gauge was jumping. “Radiation, eh?”

“Radiation. Dunno what type. The Geiger counters are quiet, so it either doesn’t register or it’s too weak to be dangerous.” Quade fiddled with the instruments. “It’s coming from the south. We passed over a good-sized crater a while back, didn’t we?”

“That’s right. It wasn’t volcanic, either. Meteoric. Suppose there’s a radioactive meteor buried down under it?”

“Possibly. But it doesn’t look like ordinary radioactivity. Let’s see.” Quade tested. “No alpha, beta or gamma types. It’s too weak to bother us, but have one of the men check on it. How about going outside? Get your suit.”

Outside the ship Quade and Wolfe sweated in the protective armor, till the refrigo-thermal systems got hold. Then they felt better. These were light-weight outfits, designed for protection against temperature and poisonous atmospheres, not the bulky, reinforced spacesuits used in pressure-work. Saturn was almost at zenith. Quade looked up at the ringed planet, squinting against the wan, yet curiously intense light.

“Have to use special filters,” he remarked. Diaphragms in the spherical transparent helmets made it possible to converse. In this atmosphere it wasn’t necessary to use radio.

Spongy pumice crackled under their feet. A bellow of crashing ice thundered from the snowy ramparts to the west. It died and there was silence. No movement stirred in the valley. Quade peered from under his palm.

“There’s a lake,” he said. “The Zonals are amphibious. Let’s try it.”

If the surface of Titan seemed a bleak desert, the waters of the satellite provided a strange contrast. The lake was an oval nearly a mile long. Its surface seethed and bubbled with glowing light—no wonder Udell had wanted to experiment with dyes! Plant-life made islands on the surface. There was ceaseless activity in the water and, every few moments, a bulky glistening body would appear briefly and vanish again.

Quade hesitated on the edge. There had been a tribe of dangerous Zonals, he remembered. In fact, there were several, news from Macao had told him—nomadic groups wandering murderously around from sea to lake to river. But most of the Zonals were peaceful enough.

And in this lake—

“Tony!” Wolfe said sharply. “Look there!”

A head broke the water a few dozen feet away. A round, furry head like a seal’s, with staring eyes. The nose was a snout, the mouth broad and loose and lipless. But for all the animalism of the creature, the curve of its head above the eyes, its obvious cranial index, showed that it must possess a brain of some intelligence.

Quade and Wolfe remained motionless. The water broke into a seething rush of bubbles and the Zonal came shoreward. It waded out and stood knee-deep in water, staring blankly.

Its body was thoroughly anthropoid in outline, and curiously graceful in its sleekly furred, streamlined contours. The Zonal was a little more than five feet tall. Its hands and feet were huge and webbed.

The Zonal squirted jets of liquid from its eyes. Then it bent and submerged its head briefly. Wolfe had involuntarily stepped back. Quade spoke softly.

“Take it easy. Its eyeballs are hollow—it’s got an opaque diaphragm stretched over ’em, like a kettle-drum. No lens. There’s a hole in the center of the diaphragm to admit light, and the hollow’s kept filled with water. Acts as a lens. It’s got perfect vision, though. And—look at that thing on its back!”

The Zonal, having filled its hollow eyes with water, stood up again, but Quade and Wolfe had already got a glimpse of the creature’s flight-sac, a great sausage-shaped object that made it look humpbacked. The sac had a gristly projection at one end that suddenly moved and twisted. The Zonal, tiring of the two men’s company, disappeared.

Wolfe was left blinking at the place where it had been. Quade, who knew what to expect, looked up. The creature was shooting through the air like a streamlined spaceship, thirty feet high and going fast. Quade pointed it out to his companion.

“Uh!” Wolfe said. “It’s worse than a flea. How does it do that?”

“Same way a squid does,” Quade explained, watching the Zonal fall like a stone toward the ground. A dozen feet above a mound of gnarled lava the amphibian seemed to halt in the air, then sank down gently, to stand quietly surveying its surroundings.

“A squid?”

“Or a cuttlefish. Squirts water out of a sac—the old repulsion principle. Only the Zonals are a little more scientific about it. Those sacs on their back look soft, but they’re plenty tough.

“They’re filled with gas, continually renewed and manufactured by letting in air and water to mix with the chemicals of their bloodstream. When a Zonal wants to move fast he lets off a blast that has the same effect a rocket-jet has on a spaceship.”

“They don’t have gravity screens, though,” Wolfe said.

Quade smiled.

“Well, no. Here’s this fellow back again.”

The Zonal came flying, bulletlike. Just before he reached the two men a blast of hissing, suddenly-released gas braked it and the creature plumped down easily not a yard away.

“Wonder if Udell taught ’em English?” Quade murmured. He put out his hand gently. “Hello, there. We’re friends—understand? We’re friends.”

The Zonal touched Quade’s flexible-metal glove with a tentative, limber finger. Then, gently gripping it in his webbed hand, he eyed it carefully, lifted it to his mouth, and took a hearty bite.’

Quade yelped, jerked his hand back and nursed a bruised knuckle. The Zonal, seemingly puzzled, lifted its shoulders in something suspiciously like a shrug and rocketed back to the lava mound, where it squatted down to think things over. Meanwhile a dozen new heads had popped up from the lake near the shore.

“I thought you said they weren’t dangerous,” Wolfe observed.

“They’re not,” Quade gulped, moving his fingers experimentally. “Ouch! That was just—ah—curiosity.”

“Well, what now?”

“We’ll unload the equipment. Get the cameras set up. The Zonals can wait a bit. I want to think things over.”

Quade was hoping he didn’t sound as baffled as he felt. He had hoped that Udell might have educated the amphibians somewhat, but apparently the creatures were dumber than apes—a lot dumber. Somehow that didn’t jibe with the sizable brain-cases of the Zonals. Their cranial indices seemed to hint that there was intelligence in those sleek furry heads—and Udell had managed to use that savvy. But how?

How, indeed?

CHAPTER IV
Crackup

Quade had arranged the compact two-man cruiser as a miniature replica of the giant camera ship and carrying identical equipment. It was a complete traveling laboratory, with built-in cameras and searchlights that could stab out from every angle through the transparent nose. During space flights it remained in its cradle within the larger vessel, but now it rested on the lava plain near by, ready for a take-off.

Three days had passed and Quade was still stumped. He couldn’t penetrate the wall of stupidity that shielded the Zonals from all advances. Once or twice he thought he was making some headway with the first Zonal they had encountered—whom Wolfe had irreverently dubbed Speedy. But Speedy, though extremely curious, shot off like a rocket whenever Quade felt he was getting somewhere.

In the great camera-ship Quade was donning his protective armor. He had decided to make a survey of the surrounding terrain in the little cruiser, on the chance that Udell’s trained Zonals might have wandered away. The icy rampart was no barrier to them, for they rocketed over it like birds.

Wolfe, leaning against a table stacked with experimental apparatus, looked tired.

“Want me to go along, Tony?” he asked.

“You’d better stay here and keep things moving,” Quade said.

“What things?”

“Yeah, I know. Everything’s ready for shooting. We could roll any time—except for the Zonals. I’ve got to find some way—”

Quade, struggling into his suit, lurched into a cabinet and deftly caught a small bottle as it fell.

“Neo-curare. Don’t want to smash that. I may use it on myself if I have to face Von Zorn without a picture.”

“Tony,” Wolfe said hastily. “I think I see Kathleen Gregg.”

“What!”

Quade whirled awkwardly, peering through the ship’s nose. A gyroplane had landed and a slim figure in gleaming space-armor was clambering out. It was, indeed, Kathleen.

“Blast!” Quade said, lurching toward a port. Halfway out he remembered the neo-curare and hastily stuck it in one of the self-sealing pockets in his suit. Pumice ground under his heels. The gyroplane, he saw, was already surging up, angling toward the ice barrier. Kathleen was trotting along briskly, but there was a certain hesitancy in the look she gave Quade.

He halted in front of the girl. She smiled.

“Why, hello, Tony.”

“Just what are you doing here?” Quade asked. “Or should I guess?”

“It’s sweet of you to say so,” Kathleen observed, tilting her nose Saturnward. “As a matter of fact, I got rather tired hanging around—”

“So you thought you’d drop in and say hello,” Quade finished for her. “Now you can turn around and say goodbye and go home.”

“How?”

Quade peered after the departed gyroplane.

“How’d you get here?”

“Took a tramp ship to New Macao and hired a pilot to fly me the rest of the way.”

“Okay,” Quade said. “See that two-man camera ship? You’re going to march into it and I’m going to fly you back to New Macao and put you on a Sunward ship. Catch?”

“Won’t,” Kathleen said, starting to run. Quade deftly caught her, lifted her kicking figure, and carried her to the cruiser. He dumped her in it and turned to Wolfe, who had followed.

“Be back as soon as I can. Keep things moving.”

“Right. Hello, Kathleen,” Wolfe said pleasantly. “Goodbye now.”

He shut the port and departed. Quade silently turned to the controls and lifted the ship. Kathleen, standing beside him, was not silent. She finished by saying that her engagement to Quade was off, and that he was a rat.

“Sure I am,” Quade said. “But this is my job and I think it’s a little dangerous. I’m sure I can handle it. Just the same, I don’t want you around. For one thing you distract me and for another I’m still wondering about that virus disease that killed Udell.”

Kathleen sniffed.

“Ha. Hey! We’re being followed.”

Quade threw a magnifying plane on the scanner. A sleek projectile was rocketing along after the camera cruiser.

“Oh, that’s Speedy,” Quade said. “One of the Zonals. He won’t follow us long.”

But this proved inaccurate. Speedy stayed on the trail for twenty miles before he was lost in the distance. Then nothing was visible but the frigid, Cyclopean peaks of the Devil’s Range, icy and alien in the pale light of Saturn.

Things began to happen with alarming suddenness.

There are plenty of safety devices on spacecraft, but these depend on the assurance that you have a skilful and a conscious operator. Quade was skilful enough, but unfortunately he was knocked cold when the vessel sideslipped in a sudden blast of air, powerful as a cyclone, that screamed up from the Devil’s Range. A geyser-heated valley below made a thermal of racing air that created a maelstrom where the icy atmosphere of Titan met it.

The camera cruiser turned sidewise and Quade went spinning into the controls. His head banged against his helmet, which made him lose all interest in the fact that the ship was plunging down.

Kathleen couldn’t do much about it, though she tried hard enough. She was wedged under a tangle of apparatus, which imprisoned her but saved her from serious injury when the ship struck, with a splash that sent water leaping high.

Creamy, luminous liquid crept over the ship’s nose. An oddly-shaped fish came to stare in pop-eyed amazement. Then it swam hastily away.

The ship grounded. Kathleen fought her way free and scrambled up the tilted floor to where Quade lay. There was blood oozing from his head, and Kathleen quickly removed the helmet and used the first-aid kit. But Quade remained stubbornly unconscious.

Two courses were left. Kathleen could fly the ship back to the camp or she could radio for help. She tried both, but without success. The controls were smashed, the gravity plates warped and broken.

The cruiser’s day of usefulness was over. The radio was hash. A telephoto camera was strewn in sections about the room and some of the carboys of concentrate-dye had torn free from their moorings and were broken. The floor was awash with yellow and pink fluid.

Kathleen peered up through the ship’s nose. The surface of the lake beneath which they lay wasn’t far above, she judged. If she could swim up—that would be easy in the airtight suit. But what about Tony?

He wouldn’t drown in ten seconds. She inflated both of the suits with oxygen, dragged Quade into the portal lock and shut the valve behind her with a futile hope that, if the atmosphere stayed in the ship, it might rise of its own accord, or at least that it would be easier to salvage the equipment. She opened the outer door and went head over heels into the rush of water. Somehow she kept hold of Quade’s arm.

Luckily, the lock was angled so that they slid out of their own accord, buoyed up by the oxygen. Quade, still unconscious, blew bubbles. With panic beginning to dry her throat, Kathleen tightened her grip on his suit and they shot up like rockets into clear, cool Saturnlight.

Quade was torn away from the girl’s clutch. She blinked and stared around. He was floating only a few yards away, his face submerged. Lying flat on the surface, Kathleen paddled to him, dragged his head up in the crook of her arm and awkwardly made for the shore.

Several sleek objects appeared above the surface and watched her speculatively. But they were somewhat different from the Zonals Quade had already encountered. Their heads were flattened, their jaws heavier. Altogether they lacked the suggestion of good nature and humanity that the other Zonals had possessed. But they did not attack, for which Kathleen was duly grateful. She finally reached the beach and dragged Quade ashore.

He had swallowed little water, being unconscious, and with a small gasp Kathleen sat down beside him, weak with relief and reaction. She looked around.

They were in a crater perhaps two miles in diameter, surrounded by overhanging peaks and glaciers that seemed to be getting ready to rush down in catastrophic destruction. This lake, a small one, was in the very center. Plumes of steam flared up here and there, indicating geysers.

Underfoot was the eternal lava, rising into a jungle labyrinth of twisted malformations. In the distance Kathleen made out a great black dome, faintly glistening. But she could not guess its nature.

Meanwhile the Zonals were swimming closer, in a semicircle. They emerged from the water, dripping, to reveal another way in which they differed from Quade’s Zonals. The sacs on their backs were shrunken and atrophied.

Kathleen found it difficult to believe that the creatures were harmless. She was eying the long, curved claws on the webbed hands, and the tusklike, capable teeth bared by retracted lips. If she had been alone she would not have waited to face the amphibians. As it was, Quade lay unconscious beside her. Neither of the two was armed.

The Zonals slipped closer. There was, Kathleen thought, unmistakable menace in their attitude. Growls rumbled from their throats. These weren’t Udell’s tame Zonals, that was certain.

Hastily Kathleen looked about for a weapon, but all she could find was a good-sized lava chunk. Hefting this, she stood up, waiting.

The Zonals, emerging from the water, closed in. Their growling was louder now. One amphibian was in the forefront; Kathleen could see him sinking lower as his furry legs bent and he tensed for a spring.

She hurled the rock.

The amphibian dodged easily. He sidled forward, and behind him came the others.

A man’s voice shouted. There was the vicious crack of a whip. Again the harsh voice roared a command. The Zonals hesitated—and Kathleen looked back hastily to see a giant figure, clothed in rags, coming forward. Gray-shot red hair bristled wildly. His face was turned toward the Zonals, but the heavy broad shoulders spoke of enormous strength.

The whip cracked. The man bellowed an order.

Snarling, the Zonals drew back. Suddenly they broke and fled to the lake. The man stood waiting till they had submerged and then turned to Kathleen. He stood quietly facing her, the whip hanging lax.

And something in his face made the girl shiver a little. The features were strong enough, even harshly handsome. But the glacial black eyes were—disturbing. There was no trace of expression in them. They stared like glazed jet marbles, cool and remote.

“My name’s Milo Sherman,” the man said. He glanced at the unconscious Quade.

As Kathleen opened her mouth, Sherman halted her with an upraised palm.

“Better talk as we go. The Zonals are dangerous.” He laughed unpleasantly. “They’re afraid of me, but I take no chances. Come on.” He bent, hoisted Quade to his shoulders and started toward the glistening dome Kathleen had already glimpsed. “Now talk,” he commanded.

Kathleen talked.

“I see,” Sherman said as they rounded a shoulder of lava. “You’re unlucky. However, you’ll be safe for a while. There’s my castle, see?”

Fifty feet away the building loomed, a dome-shaped structure as high as a six-story building. It seemed to be built of some gleaming black substance, broken at intervals by round gaps. Sherman marched forward, straight toward a blank wall.

No—not entirely blank—there was an inch-wide hole in it. And the hole began to broaden as they approached, opening till it was a gaping portal.

They stepped across the threshold. Behind them the hole shrank again, like a sphincter. They were in a large room, bare except for a sloping ramp that led up to a gap in the ceiling. A row of luminous spots glowed in the walls.

Sherman went up the ramp. Kathleen was behind him, a little troubled now, conscious of some unknown danger. Above, the room was larger, lighted by similar lightspots in the walls. It was filled with a clutter of junk—chairs, tables—some of them twisted and broken—most of them rusty.

“Salvage,” Sherman said. He went to a corner, dropped Quade into a shallow depression in the floor and tossed his whip aside. Quade’s body sank down a few inches, as though into an air mattress.

“Well, take off your helmet,” Sherman said coolly. “Make yourself at home. You’ll be here for life—since there’s no way of getting out of this valley!”

CHAPTER V
Perilous Valley

Kathleen sat down limply on a rusty chair that squeaked under her weight. Her fingers felt cold and clumsy as she unscrewed her helmet, deflated the spacesuit and shook her hair free.

“No way out?” she said. “We could climb—”

“You could try it,” Sherman said, “till you got tired. The glaciers wall us in. And they crumble. I broke my arm six years ago trying to escape.”

“Six years!”

“I’ve been here seven,” Sherman told her. “I’m the last survivor of the patrol ship Kestrel, wrecked while making a forced landing in the Devil’s Range. Three of us escaped with our lives from the crash—the ship’s doctor, myself and another patrolman. Their graves are down the valley a bit.” His eyes were blank.

“Seven years here, with the Zonals gradually losing their fear of me. They multiply faster than I can kill them. Now I’ve got about eight rounds of ammunition left—no, nine, I see.” He showed an old-fashioned pistol.

“But the camera crew will search for us.”

“A tiny valley in three hundred miles of mountains? And your friends won’t know where to look, from what you say? For all they know, you might have crashed anywhere on Titan.”

He hesitated.

“I’d forgotten something. You’ve got to be inoculated immediately. Otherwise you’ll just go crazy and die.”

Kathleen blinked. “Huh?”

“The plague—the one you say killed that man Udell and his crew. It nearly killed us before the Kestrel’s doctor got on the track. You’ve got the virus in you now.”

“That’s impossible,” the girl said. “Unless we were infected since we cracked up.”

“You were infected before you ever landed on Titan,” Sherman said grimly. “The virus is a protein molecule that exists in living organisms—Zonals and humans alike. Usually it’s harmless—a recessive characteristic. But under the influence of a certain kind of radiation the virus becomes actively malignant.”

“I don’t get it.”

Sherman had talked a good deal with the Kestrel’s doctor before the latter died. He told Kathleen about the tobacco mosaic disease—how a plant, suffering from common mosaic disease, may suddenly become victim of a more virulent form—acuba—caused when the basic molecules change their structure.

“It’s like that,” he said. “There’s a meteor on this continent which emits rays that develop the latent, harmless virus in one into the active, malignant form. That’s what originally wrecked the minds of the Zonals, you know.” He noticed Kathleen’s pallor.

“Don’t worry too much about it. I’m still alive, you see. Our doctor worked out a cure. The Zonals have antibodies in their bloodstreams—antibodies strong enough to immunize a human. They developed ’em, but not in time to save themselves from degeneration. I prepared a fresh batch of serum yesterday—so come along and I’ll inoculate you.”

“But—will Tony—”

“He’ll be safe here. The Zonals don’t dare come into my castle.”

Kathleen followed Sherman through another of the sphincter doors. She was thinking of Wolfe and his crew. They were also exposed to the meteoric radiation—which would eventually kill them unless they were warned and immunized.

But when Kathleen told Sherman, he merely shrugged.

“We’re in prison here. No radio. No way of communication. Your ship’s under water and wrecked. So—” He picked up a hypodermic syringe. “You and your friend—what’s his name, Quade?—you’ll be safe enough, unless the Zonals kill us. They can’t come in here.”

“This building? Who made it, anyway?”

“The Zonals,” Sherman said. “A long time ago. They were a plenty intelligent race before the meteor landed and the plague hit them. I’ve got an idea there used to be a lot of these castles on Equatorial—bigger ones than this, too. It’s not exactly a building, though. It’s alive.”

“Alive? How?”

“Hard to believe, isn’t it? I guess there’s nothing like these castles anywhere else in the System.”

“The studio biologists make robot animals,” Kathleen said doubtfully.

“Yeah? These castles were made by the Zonals once—to live in. As though a lot of blood corpuscles had got together and built a man to live in. These castles don’t wear out and they don’t need electricity or air conditioning—they’ve got everything. Notice how fresh the air is?”

“I hadn’t. But I do now.”

“That’s air conditioning. The castles breathe—they take in air, filter out the harmful bugs and cool or heat or humidify it if necessary. You don’t need windows for light, with those eye-spots in the walls.”

The syringe was ready. Sherman made an awkward but careful injection in Kathleen’s arm.

“You’re safe enough now,” he said. “You’re immune. But you’ll need occasional booster shots. I’ll fix up your friend next. Look around the castle if you want—it’s safe enough, as long as you don’t go outside.” He refilled the syringe and departed.

Kathleen sat down to wait for the inoculation-shock to wear off. It was some time later when she heard a confused clamor from outside. Hastily she rose, found the weakness had passed and hurried to the room where she had left Quade. He still lay unconscious, the syringe at his side and a wad of cotton still sticking to his bare arm. Sherman was gone.

Outside the yelling of the Zonals stilled. Sherman’s voice rose. The growling began. It rose to a roar. The whip cracked violently, but the noise did not stop, though it sank to a harsh murmur.

Presently Sherman came back into the room, dragging his whip. His eyes were bleak as ever, but a muscle was twitching under his eye. Without pausing he said, “You’ve set off the Zonals.”

“I did? How?”

“Ever since I landed here the food supply in the lake has been diminishing. Before that, too, I suppose—but it got below the danger point not long ago. The lake’s nearly cleaned out. There’s another little pool ’way up at the end, but that’s empty too, now.

“The Zonals are hungry. Which adds up to the fact that they figure we’re good to eat. I told ’em to go catch fish—there must be a few left—but they didn’t understand me, of course.”

Kathleen gulped. Sherman grinned at her. He went through one of the sphincter doors and came back with the whip in one hand and a long knife in the other.

“I may have to fight,” he said. “Our little friends are getting anxious outside. Here’s my gun. If they get past me—use it.”

The next ten minutes were far too long. It was impossible for Kathleen to guess what was happening outside; she could only listen to the muffled snarling and the incessant crack of Sherman’s whip. Once Quade moaned and stirred and she turned hastily to him, but it was a false alarm.

Sherman backed into sight. He was retreating very slowly, using both the lash and his knife. Beyond him the Zonals pressed forward, snarling.

“Shall I shoot?” Kathleen asked softly.

“Not yet,” Sherman said without turning. “Save it till—”

He stopped talking, for the Zonals’ growling rose to a roar. They flooded forward into the room, forcing Sherman to give ground. He swung his whip—and it was caught, dragged from his hand. He went down under the rush of the amphibians.

Then the creatures were everywhere. Before Kathleen had a chance to fire, the gun was knocked out of her grip. The Zonals moved far faster than she had anticipated. She struck out desperately, hearing Sherman’s hoarse curses as he slugged and battled under a mound of Zonals.

And just then the gun exploded. A concerted wave of panic caught the amphibians. They gave ground as the gun crashed again.

It was Quade, on his feet now, placing his shots accurately. The Zonals were beginning to drift toward the door, a movement that grew into flight and then to panic. In a minute or less the room was empty except for the three humans.

Sherman got up, rocking unsteadily.

“Lucky I didn’t use the gun much,” he said. “They’re plenty afraid of it. But we’re out of ammunition now.”

“A fine thing to wake up to,” Quade said, sitting down and turning a pale green. “What’s been going on? Kathleen—”

She told him.

CHAPTER VI
Poisoned Javelins

It was indeed alarming news.

“Unarmed, eh?” Quade said when she had finished. Sherman had gone out of the room, but now he came back in time to hear the words. He was carrying a bundle of sharpened metal rods.

“Only these,” he said. “I ground ’em a long time ago.”

“Javelins? Mm-m.” Quade dug into a pocket of his spacesuit. “Neo-curare,” he said, bringing out the bottle. “Lucky I brought it along. If we smear some of this stuff on the points, it ought to account for a few Zonals. It’s a fast-acting poison. Anything going on outside?”

There was nothing. They stood in the castle’s door-sphincter. As it automatically widened, the barren wilderness of the valley became visible. No Zonals were in sight. The lake glowed phosphorescently in the distance.

“Here comes something,” Kathleen said.

With a swish and a thump something rocketed into view, plumping down just outside the threshold. Quade stopped Sherman’s lifted javelin-arm.

“Hold on. He’s not dangerous. This is Speedy, one of my tame Zonals. He must have trailed us here.”

It was Speedy, all right and Speedy was staring with wild curiosity at Quade and the others. The contrast between this amphibian and the degenerate Zonals of the valley was marked. The fangs and claws of the decadent tribe didn’t show in Speedy, and his high-arched cranium hinted at intelligence, not brutal ferocity alone.

“Pencil and paper, quick!” Quade said. “We’ve got a carrier pigeon here!”

Sherman vanished. He reappeared in a moment, bearing a small metal cylinder and a length of wire as well as writing equipment. Quade hastily scribbled a note, thrust it into the cylinder and cautiously approached Speedy.

The Zonal almost got away, but was betrayed by his suspicion that Quade’s hand was good to eat. Quade held the amphibian firmly while he fastened the cylinder to Speedy’s body and tried to keep his hands out of reach of the nibbling mouth at the same time.

“Hope he doesn’t know how to untie knots,” Kathleen said. “How about it, Tony? Will he head back for the camp?”

“I don’t know,” Quade said. “Still, that’s where he lives.” He released the Zonal. “Blow. Take a walk. Rocket off!”

Speedy reached for the metal tube. Quade yelled and clapped his hands, and the amphibian rocketed away in alarm. He came down fifty feet away, near a mound of lava and went to work on the wire.

Quade started toward him, running. From behind the lava block came two of the decadent Zonals, closing in on poor Speedy. He didn’t see them until too late, and then he went down under the rush, fighting with feeble valor.

Quade stopped. He couldn’t reach the battle in time, but he still held a poisoned javelin. He hurled it at the struggling group.

Speedy yelped, waving a bleeding arm grazed by the metal point. Quade was a poor marksman with this unfamiliar weapon.

But Sherman was a better one. His javelin struck one of the attacking Zonals and got him through the heart. The other, taking alarm, fled.

Speedy lay limp and unconscious. Quade started to run again, hearing footsteps behind him. He felt slightly sick. The last chance for escape was gone now. Then his eye caught a flicker of motion. Speedy wasn’t dead. He grunted, stood up, swaying, and stared around.

A yelling came from the lake.

“Come on,” Sherman said urgently. “Let’s get back to the castle. We haven’t a chance here in the open.”

Speedy suddenly rocketed away. Quade saw him land beside Kathleen at the castle’s doorway. The two men fled, hearing the thud of racing feet and the roars of the Zonals rising in volume. They reached the castle—and Quade got the shock of his life.

“They try kill us, yes?” an unfamiliar voice said hoarsely.

Quade looked at Kathleen, then at Sherman. They, too, were staring. Again the voice repeated its question. Slowly Quade turned to meet the unblinking gaze of Speedy.

“This bad place,” the Zonal said. “Better go.”

“He talked,” Kathleen murmured unbelievingly. “He’s intelligent, Tony!”

“Intelligent,” Speedy repeated. “Yes. Your language hard. But Earth man Udell taught us some words. Speak.”

Quade swallowed.

“Yeah. You speak, all right. But how? Have you been playing dumb all along?”

Speedy looked puzzled.

“Earth man Udell stick us with needle.”

“That’s it,” Quade said abruptly. “So that was Udell’s trick!” He glanced around. “We can’t get out. Our ship’s wrecked. Understand?”

Speedy nodded.

“Understand. I get help.”

“You know where the camp is?”

“I know. I go there now. Tell men—bring them here. Yes.”

He rocketed up and was gone. His sleek figure was visible swooping toward the ice barrier. Then he had crossed it and vanished.

“Let’s go inside,” Quade said. “I’d hate it if the Zonals ate us before Wolfe got here.”

Inside the castle Quade divided the javelins and passed them around.

“One mystery’s solved,” he said. “There won’t be any trouble in filming Sons of Titan now. The Zonals are intelligent—but it takes a shot of neo-curare to make ’em that way.”

“A poison?” Kathleen asked. “Spill it, Tony.”

“A poison to us, not to the Zonals. They’ve a different sort of physiology. The neo-curare doesn’t hurt ’em. It just liberates their subconscious.”

“Huh?” Sherman said.

“Here’s the angle. Scientists got on the track a long time ago—’way back before nineteen-forty. They experimented with a dog—trained him to do certain things at the sound of a bell, a conditioned reflex, you know. Then they doped him with curare and developed other habit-patterns in his brain, also set in action by the bell.

“They proved the two had two independent behavior-systems in his mind—that both could be trained to react to the same stimulus and do it independently of each other. It works like that with the Zonals.”

Kathleen blinked. Quade went on.

“It’s logical enough. The virus that wrecked the Zonal culture ruined only their conscious mind—made ’em idiots. Their subconscious minds weren’t harmed. They still retain their potential power. But they’re subconscious, of course—blanketed.

“The neo-curare simply inhibits the higher centers of the brain, the part that was wrecked by the virus, and releases the subconscious. And while that’s in control the Zonals are intelligent! This will mean rehabilitation for the whole race, someday. Udell taught and trained ’em while they were doped with neo-curare.

“So all we have to do is follow Udell’s lead. When we get back to camp we’ll first of all immunize the men with the antivirus and then break out the neo-curare. We can finish Sons of Titan in a few weeks!”

“You forgot something,” Sherman said. “One of the degenerate Zonals got inoculated with neo-curare too, just now.”

“Well, the javelin also went through his heart,” Quade said. “You can’t be smart when you’re dead. I dunno about that but I’ve got a suspicion the neo-curare won’t have the same effect on these Zonals of yours. They’re so decadent that even their subconscious may be bestialized.

“They’re almost a different race, as far beneath the regular Zonals as a hyena is beneath a human being. We can try it out and now’s our chance, because they’re attacking again. So we can’t wait till Wolfe arrives. Kathleen, our ship’s wrecked, isn’t it?”

“I think so,” the girl said dubiously. “The plates are smashed.”

“Um. I may be able to do some repair work. It’s worth trying. Your helmet’s okay, isn’t it?”

Kathleen nodded.

“But you’re not going outside, are you?”

Quade was donning his spacesuit. He pulled the transparent helmet into place.

“I am,” he said through the diaphragm. “Our javelins won’t keep the Zonals off long unless the neo-curare will do the trick—and I’m going to find out. At worst, even if our ship’s wrecked, there’s a gun or two in the cabin.” He turned to Sherman. “Take it easy. Luck.”

“I’m going with you,” Kathleen decided.

“There’s only one helmet,” Quade informed her. “I’ll be safe enough in this spacesuit. You stay here till I get back, understand?”

“All right,” the girl said obediently and Quade departed.

“First time in her life she ever did what I told her,” he thought, plodding toward the lake. This job was going to be dangerous, regardless of what he had told Kathleen. If the Zonals attacked—

He went on. A number of the Zonals trailed him. One ran forward, and Quade spun quickly and threw his javelin. He didn’t want to kill. He was making an experiment. The sharp-ground point ripped into the amphibian’s leg and the Zonal fell instantly.

Quade waited. After a minute or more the creature hoisted itself laboriously upright. It had fallen behind its fellows, who were still following Quade.

It ran after them, limping. Its low snarling mingled with the menacing noises of the others. One glimpse of the amphibian’s brutal face told Quade that his guess had been right. These Zonals were so decadent that not even neo-curare could make them intelligent.

Shrugging, he turned to the lake. A gleam of metal told him the location of the sunken spaceship. Quade waded in. The luminous water seethed about his knees, his waist—closed over his helmet. That didn’t matter. The chemicals in the suit supplied plenty of air.

He saw the ship, a black shadow, looking like a great resting shark on the bottom. Thanks to the luminosity of the water it was surprisingly clear; he could make out details easily. And now he could hear noises that must mean pursuit. The Zonals, he thought, were amphibians.

They swam down, keeping a safe distance for the time as Quade manipulated the space-lock. As the Zonals saw him disappearing they came in fast. Quade got another javelin from his belt and used it efficiently.

But after that he was reduced to using his fists, which was not too effective under water. The Zonals began dragging him out of the lock. Quade reached out, caught a lever, and tried to anchor himself. He couldn’t.

But inside the ship there were weapons.

He struck out frantically at another lever. The inside port opened. The sealed ship became unsealed in an instant, and the lake poured in, carrying with it Quade and a dozen Zonals. By the time the water had settled, a steady stream of amphibians were swimming down through the open lock, and the water had changed color to streaky yellow and pink that gradually merged into an ambiguous darker hue.

Briefly puzzled, Quade noticed that two carboys of the concentrated aqueous dye had been smashed. Also, Kathleen had left the ship’s lights on, so the Zonals, temporarily distracted, were able to see Quade and to converge on him.

They got him down, clawing at his suit with their talons. That didn’t worry him. The armor was tough. But one of the Zonals, after breaking a tooth on Quade’s helmet, got a bright idea. He found a metal bar somewhere and began smashing it down on Quade’s head. He used it like a piston, so that water pressure was minimized, and the helmet began to show a webwork of fine cracks.

Quade twisted, got hold of the bar and tussled it free. He levered oxygen into his suit hurriedly. Buoyancy took over, and he shot up out of the heap of Zonals and bounced off the ceiling. But the amphibians instantly swam up after him.

It was then that Quade noticed the row of carboys in their wall-cradles beneath him....

He broke them. Using the metal bar, he floundered and fought and smashed his way through the Zonals down the line, while blue and green and translucent orange flowed out from the carboys, staining the water brilliantly. It was tremendously concentrated, this aqueous dye.

And, while each dye had been made to blend transparently with water, there is a simple principle of the color-wheel that added up to complete opacity. If you mix a lot of colors, you get black. This wasn’t dead black, but it was darker and thicker than a Venusian fog on Darkside.

Within moments the Zonals were fighting by touch alone. Luckily for Quade, they had no scent-organs worth mentioning, or could not use them under water. And they did not know the spaceship, while Quade could have found his way from bow to stern blindfolded.

He was blindfolded. But the Zonals were in a worse predicament as Quade found when he opened the arsenal, abstracted a few weapons and dodged his way out of the dun-colored lake to shore. Some of the amphibians were emerging on land, but they were wandering around vaguely, with helpless, groping motions.

They had hollow eyeballs and used water for lenses. Thus, since they’d sucked in the dark-dyed lake-water by now, they were blinded until they could find clear liquid of some sort!

Hordes of them were emerging from the lake. They were grouping together now, stumbling up the valley toward the pool at the upper end. There they could regain their vision. But it would take time, and Quade, his arms loaded with blasters and thermo-pistols, grinned tightly and started back toward the castle.

No Zonals were visible when he reached it. Kathleen and Sherman ran forward to meet him. Quade let the guns fall.

“Wait’ll I take off this suit,” he said, and unzipped himself. Sherman was lovingly loading the weapons as Kathleen helpfully tried to pull off Quade’s helmet without loosening the bolts.

“Okay,” Quade said, beating her off. “I’ll do it. There! Now. Let me tell you what happened.” He explained. Sherman whistled.

“Blind man’s buff! That should hold the Zonals for a while. They’ll be all right after they get to the upper pool and rinse their eyeballs out, but it’ll take a while. And with these guns—” He touched a thermo-pistol with expert fingers. Then, suddenly, he looked at Quade.

“I just thought—I hadn’t realized it before! I’ll be getting out of here! After seven years—”

The big shoulders shook.

“I’ll take this gear inside,” Sherman said.

He didn’t finish. Carrying the guns, he went into the castle and the portal shrank behind him.

“Give him time,” Quade said slowly. “Let’s wait here for the ship.”

So they did. And when it loomed over the glaciers Kathleen sighed, relaxed against Quade’s shoulder.

“Now we’re all set, huh?”

“Right,” Quade told her. “Because you’re going back Sunward with Sherman. He’s got to report to Patrol headquarters and I’m going to have him take you with him.”

“Tony!” Kathleen said reproachfully. “You don’t love me any more!”

“I adore you madly,” Quade said, ignoring the sputtering girl as he signaled the approaching ship. “You hate me. Our engagement’s broken again. You’ll get Von Zorn to blacklist me. You’ll elope with a crooner. I know exactly what you’re trying to say. Just the same, you’re going Sunward with Sherman. I’ve got a picture to shoot! You hear me?”

“Of course, Tony,” murmured Kathleen, who was already laying new plans. “But I just happened to remember. What about the Planetary Quarantine laws? We’ve all been infected with this Titan virus and, even though we’ve got the antitoxin, we’ve got to stay on Titan for thirty days—or is it sixty? Don’t look at me like that! I can’t help it, Tony—honest I can’t—it’s the law—!”