Part 5

He had to repeat the command twice before Sampson understood. Then the big man bent, fumbling with the lock, working with agonizing slowness.

Hours seemed to drag past before Sampson straightened.

* * * * *

Garth tried the door. It opened. The first step was accomplished, anyhow. The others would be more difficult. He was unfamiliar with the underground city. How the devil could he evade the Zarno and find a hiding-place? Alone, he would have a better chance. But he had twelve companions to take with him.

He spoke to each of them. "Follow me. You understand? Follow me till I tell you to stop. Move as quietly as you can."

Then he led them out of the cell.

The city, as he speedily learned, was a labyrinth. Luckily there were innumerable cross-passages. And all the cities of the Ancients had been built along a similar plan. Garth knew the layout of Chahnn, and that helped him now. But there were times when he had to move fast, and the others walked as though striding through water.

"Quick! In here! _Fast!_"

And they would follow him, into a side tunnel, while the heavy, metallic foosteps of the Zarno approached like the drums of doom.

But there was no place to hide permanently. Worst of all, a distant clanging sounded presently, and Garth guessed what that meant. The escape of the captives had been discovered.

Gingerly he skirted the huge cave where the dais was, glimpsing the giant robot in the distance, and shepherding his charges along a twisting corridor that led down. But the footsteps were growing louder. Garth was almost certain that they were following.

He increased his pace, with wary glances behind him. Unless he found a side passage soon, the swift Zarno would speedily overtake them.

"Faster! Move faster!"

The Earthmen tried to obey. Like automatons they ran, their eyes fixed and staring, while the clamor of pursuit grew louder. Looking back, Garth saw a flash of shining movement The Zarno!

"Faster!"

There were no side tunnels. They came out into a small cave, completely empty. It was a cul-de-sac. Light was reflected brightly from three walls.

The fourth wall was dead black--neither rock nor stone. It was like a jet curtain, blocking their path. Garth jerked to a halt, knowing the utter hopelessness of futility. They were trapped now.

The Zarno were pursuing, unmistakably.

Garth took out his useless gun. His face was set in grim lines. What good were bullets against the silicate creatures?

But waiting helplessly was far worse. At least he could try to fight.

He had forgotten to command his charges to halt. Glancing around, Garth saw something that made his eyes widen in incredulous amazement. Paula was walking toward the black curtain--the wall--

She stepped through it and vanished.

Brown followed her. Then another man. And another.

Last of all, Sampson, disappearing like a ghost through the blackness!

Heavy footsteps whirled Garth about. Down the corridor he could see the flashing gleams that heralded the Zarno. His tight grin was a grimace.

"The hell with you, pals," he said softly--and turned again. He raced in pursuit of the others.

Leaped through the dark curtain!

* * * * *

There was an instant of grinding, jolting shock that left him blind. He staggered, caught himself, and saw that he was in a passage that led toward a distant brightness. Silhouetted against the glow were the moving figures of his companions.

He sprinted after them. But he did not overtake them till they had emerged in a cavern unlike any he had seen before.

"Okay! Stop! Stop, that's right."

They halted, motionless. Garth looked behind him, but there was no trace of the Zarno.

This cavern was lighted like the others. But there were fewer machines. Row after row of the giant four-armed robots stood like an army on the dark-metal floor. The walls were jeweled, thousands of pearly disks studding them. A low humming came from a machine nearby, a tripod with lenses surmounting a square box.

Garth walked through it. He hesitated, glanced around again, and then peered through the lenses.

A voice seemed to speak within his brain.

"--invoked the rule of silence. After that, Genjaro Lo declared that space travel was inevitable and might solve the natural problems of our civilization--"

It had spoken in the Ancient Tongue. And, at the same time, Garth had seen a picture of a huge, four-armed being with a bulging, yet oddly symmetrical head, standing on a rostrum addressing a multitude--

"_Ed!_" The voice rang through the silent cavern. "Ed Garth! You made it!"

Garth whirled. A man had emerged from a cavern-mouth nearby, a short, slight man with white hair and a lined, tired face. He ran forward, his ragged garments flapping, his eyes shining.

Garth said, in a voice like a prayer, "Doc Willard. _You're alive!_"

VIII

Willard gripped his friend's hands. "Alive, yes. If you can call it that. I've been living for only one thing. I knew you'd come back, with help, if you got through. And you did!"

The cavern was spinning around Garth. He braced himself, staring at the man.

"Doc! I've been going crazy for five years. I thought I--I'd killed you."

Willard stared. "Killed me? But--"

"That altar!" The words tumbled out of Garth's mouth. "I couldn't remember much. That damned Noctoli poison--I lost my memory. But I knew I'd tried to knife you while you were stretched out on an altar--"

Sympathy showed in Willard's eyes. "Good Lord, Ed! And you could remember only that? You must have gone through hell."

"I did. I didn't know what--"

"But we planned it. The whole thing. A fake ceremony, to impress the Zarno and give us a chance to escape. They thought we _might_ be messengers from their gods--the Ancients--and we told 'em so, after we'd learned their language. The sacrifice--it was a fake, that's all. And it went through as we planned. You pretended to stab me, and while the Zarno were bowing and genuflecting, we got away. At least you did. They recaptured me."

Garth shook his head. "Tell me. I don't know, really."

Willard glanced at the Earthmen, curiosity in his eyes. "You've a bit of explaining to do yourself, Ed. Are they--Noctoli?"

"Yeah. I worked out an antitoxin, but it was stale." Quickly Garth explained what had happened.

"I see. Well--got a cigaret?" Willard sucked the smoke luxuriously into his lungs. "That's good. Five years since I had one of these. Sit down and let's talk. No chairs, but try the floor."

"Okay. What happened to you?"

"Nothing much. When we staged our fake ceremony--the Zarno are plenty religious--I headed for that little black temple in the forest. Know the place?"

"Yeah. That's where they caught us."

"Well, it leads to freedom. There's an underground tunnel that takes you out in a camouflaged hangar. The Ancients had antigravity. I found out later, and their flying-boats were hidden there. They're still good, Ed. They still work. I'd have got away if the Zarno hadn't been right on my heels."

"So?"

Willard nodded. "The controls are easy. A couple of push-buttons and a steering-lever. I'd got a few feet off the ground when a couple of Zarno jumped into the boat with me. They heaved me out and followed. The flying-boat went off to Mars or somewhere, I suppose--it kept on going straight up. But there are others. Only I've never been able to get at them. If I could have, I'd have headed for Oretown, pronto."

Garth's eyes were glowing. "If we could reach that hangar, Doc, we could escape--all of us."

"Sure. Only we can't. Too many guards. It's impossible to get out of this city. I've tried often enough. The only way I managed to survive was by entering the Darkness." His voice trailed away.

"That black wall?"

"It's a vibration-barrier. None of the Zarno can pass it. It shakes them to pieces--destroys them. The Ancients made it, I suppose, to guard their library." Willard extended his hand in a sweeping gesture. "This is it. All the knowledge of the Ancients--tremendous knowledge--compiled here for reference. If we could only get it out to the world!"

Garth remembered something. "Does it mention their power-source?"

"Sure. I've had nothing to do for five years but study the library. I could put my finger on the wire-tape recording that explains the process. It's an intricate business, but we could duplicate it on Earth easily enough."

Paula would be glad to know that, Garth thought. The secret of the Ancients' power, that could replace oil and coal--a vital secret to Earth now.

* * * * *

Willard was still talking. "I ran when I heard you coming. I'd been studying one of the recordings, but I thought the Zarno might have got through the barrier somehow.... It doesn't harm humans, luckily, or the robots. I learned a lot in five years."

"How did you manage to keep alive?"

"I found food. The Ancients had stocked up this place. _Pills!_" Willard grimaced. "They kept me alive, and there was a machine for making water out of the air. But I'm hungry for a steak."

Garth scowled. "Doc--one more thing. You know what I mean?"

Willard sobered. "I get it, Ed. The cure. Whether or not I--"

"Whether or not you've found the cure for the Silver Plague. It hasn't been checked yet. It's still killing thousands on Earth."

"So. I wondered a lot about that. Well--the answer is yes, Ed. I know the answer."

"The cure?"

"Yes. I worked it out, completely, with the aid of the Ancients' library. They were studying it too, but they didn't have quite the right angle. However, they were able to supply the missing data I needed." Willard took from his pocket a small notebook. "I had five years to work on it. So far, of course, it's theoretical, but everything checks. It's the cure, all right."

Somehow Garth didn't feel much excitement. Five years ago, he thought, that notebook would have saved Moira's life. Now--well, it would still save life. It would save Earth. But--

He shrugged. "Two good reasons to get back to civilization. The cure, and the secret of the power-source."

Willard nodded. "The Ancients died of the Silver Plague, indirectly. They tried to escape by changing their bodies. The library told me that."

"Their bodies? How?"

"Well--you've seen the robots in Chahnn and here. Originally they were the servants of the Ancients."

"Intelligent?"

"No--not in the way you mean. They could be conditioned to perform certain tasks, but usually they were controlled telepathically by the Ancients, who wore specialized helmet-transmitters for the purpose. The robots had radioatomic brains that reacted to telepathic commands. Then when the Silver Plague struck, the Ancients tried to escape by transplanting, not their physical brains, but their _minds_. I don't quite know how it was done. But the thought-patterns, the individual mental matrix, of each Ancient was somehow impressed on the radioatomic brain of a robot. Their minds were put into the robots' brains--and controlled the metal bodies. So they escaped the Plague. But they died anyway. Human, intelligent minds can't be transplanted successfully into artificial bodies that way. So--in a hundred years--they were dead, all of them."

So that was the secret of the Ancients' disappearance from Ganymede. They had taken new bodies--and those bodies had killed them through their sheer alienage.

Willard crushed out his cigaret-stub. "All the knowledge of the Ancients at my finger-tips, Ed. You can imagine what research I've done!"

"I should have thought you'd have looked for a weapon against the Zarno," Garth said practically. "The Ancients were able to conquer them."

"I did--first of all, after I'd learned how to work the recording-machines. A certain ray will destroy them--a vibrationary beam that shakes them to pieces, disrupts their molecular structure. The only trouble is--" Willard grinned sardonically. "It takes a damn good machine shop to build such a projector."

"Oh. We couldn't--"

"We couldn't. The Ancients left plenty of apparatus here, but not the right kind. Mostly records, and a lot of robots. Sorry, Ed, but unless you brought good weapons with you, you're stuck here with me."

* * * * *

Garth looked around to where his companions were standing motionless. "Yeah. Looks like it. Unless we can break through to that hangar of antigravity ships--"

"We can't. The city's full of the Zarno, day and night. And there are always guards outside."

Garth sighed. "The trouble is, unless we get out, nothing can stop the Silver Plague. Not to mention the fuel shortage. Wait a minute. You said the Zarno were superstitious--we tricked them once with a fake ceremony. Couldn't we try that again?"

"I did," Willard told them. "It didn't work. The Zarno know what human beings are like now. Only the gods would impress them--those robots who once were their masters."

Garth stopped breathing for a moment.

"There's a way," he said.

Willard looked at him. "I don't think so. When I saw you'd come back, I hoped for a minute--but it's no use. The Zarno are invulnerable to any weapons we can create here. We can't get out of the city!"

"You said the gods would impress them."

"The gods are dead--the Ancients."

"Suppose one of them came back?"

Willard caught his breath. "What do you mean?"

"Originally the robots were controlled telepathically. Why can't that work now--for us?"

"Don't you imagine I thought of that? But it's no use, without one of them helmet-transmitters. And there aren't any...." Willard sucked in his breath. "Hold on! I'd forgotten something. There's one transmitter left--just one. But it's not a portable."

"Swell!"

"Wait a minute. Come over here." The older man led the way to a tripod-projector, found a cylindrical black object, and slipped it into place. "Look at this."

Peering through the eye-pieces, Garth recognized the great cavern with the dais at one end. The scene shifted, showing the gigantic twelve-foot robot sitting on its throne, a solid block of black metal.

"Watch," Willard said.

A voice spoke in Garth's mind, in the Ancient Tongue. "It was necessary to impress the superstitious Zarno. Thus we created this robot god and placed it on its throne. Its radioatomic brain can be controlled telepathically by means of a transmitter concealed within the throne."

The scene changed, showing the back of the ebony block. A hand, inhuman, six-fingered, came into view--the hand of an Ancient. It touched a concealed spring, and the throne's back slid open, revealing a compartment easily large enough to hold a man.

"Here is the transmitter. It is placed on the head and the will focused on issuing telepathic commands to the robot god on the throne."

There was more, but now Garth watched with only half his mind. He scarcely saw the details of the ritual ceremony with which the Ancients had impressed the Zarno. When the vision vanished, he swung about, a new light in his eyes.

"That's it, Doc! That robot god's going to come to life!"

* * * * *

Willard frowned. "_Um-m._ The gadget isn't difficult to operate--I've learned that much from the recordings. You just think hard, that's all. But--"

"The god will come to life and summon the Zarno--all of them. The rest of you can escape while I'm keeping 'em busy."

"Hold on!" the doctor snapped. "Why you? It's my job, if it's anybody's."

"Sorry," Garth said. "It doesn't work out that way. You're the only guy who can cure the Silver Plague. Unless you get out safely, it's the end of Earth."

Willard didn't answer. Garth went on swiftly.

"You could reach the hangar if it weren't for the Zarno. Well, I'll get inside that throne and start the ruckus. That'll give you time." His voice was emotionless.

"How do you know you could reach that temple-cave? The city's full of Zarno."

Garth shrugged. "It's a chance we've got to take. The only one."

Willard chewed his lip. "Why the devil do you have to be the one?"

"Because I know the Ancient Tongue. The robot can talk, can't it? Well! It's between you and me, Doc, and you're the boy who can cure the Silver Plague. You can't get away from that."

"I-I suppose so. But--"

"You know the way out. Give me time to reach the temple and begin the ceremony. Then lead the others out. They'll obey you; they're in the Noctoli trance. Get 'em to the hangar and light out for Oretown. Be sure to take the recording of the power-source with you."

"You crazy fool," Willard said through stiff lips. "What about Moira?"

Garth's face went gray. "Moira died years ago," he said carefully. "It was the Silver Plague."

Doc didn't reply. But he nodded as though he had unexpectedly learned the answer to a problem that had been puzzling him.

"Okay," Garth said. "You know what to do. Give me time enough to make it. Then get out of here with the others, fast."

Willard's hand gripped Garth's. "Ed--"

"Forget it."

He moved toward the tunnel-mouth. Paula, he saw, was lying near by, her red-gold hair cascading about her pale, lovely face.

Garth stood looking down at her for a long moment. Then he went on, into the tunnel that waited for him. He did not look back.

Cautiously he stepped through the black curtain, ready to retreat at sight of any Zarno. But the cavern was empty.

If he could make it--!

Noiselessly he stole up the passage. Once he froze against the wall at the sound of distant footsteps. But they faded and were gone.

He came out at last into a corridor he recognized. Far away, he saw the flashing gleam of the Zarno's silicate skins. They were approaching, but apparently had not seen him yet.

He raced for the archway that led into the temple-cavern. If there were any Zarno there, it would be fatal. But luck favored him. The immense room was empty. At the far end the huge robot sat on its jet throne.

Garth sprinted across the floor. He could hear voices growing louder in the distance, and the thumping of the Zarnos' footsteps, but he dared not risk a glance behind. Could he make it?

He jerked to a halt, springing behind the throne, its bulk temporarily hiding him. The Zarno were in the temple-cave now; he could tell that by their voices. Hastily he sought the secret spring.

A panel opened in the ebon block. It was exactly as he had seen it on the tripod-recording machine, a fair-sized cubicle with light coming faintly through a vision-slit in one wall. Garth wedged himself in and slid the panel shut behind him, gasping with relief. Peering through the slit, he found he could see the entire cavern. Three Zarno were approaching.

The robot, seated on the throne above him, was, of course, invisible. Garth stared around, trying to remember the details of the Ancients' recording. A helmet transmitter ... there it was, attached by wires to the low ceiling. Warily Garth slipped it upon his head.

What now?

A flat black plate, like a diaphragm, was set in the wall slightly above his head as he crouched. This hiding-place, he realized, had been built for the larger bodies of the Ancients.

Closing his eyes, he tried to concentrate. Doc Willard had said the helmet-transmitters worked that way. Telepathy--will-power--

"_Stand up!_" he commanded silently to the unseen robot above him. "_Stand up!_"

There was a stir of movement. Garth, peering through the slit, saw the three Zarno jerk to a halt.

One of them cried, "The gods return! _Kra-enlarnov! The gods!_"

* * * * *

Garth put his mouth close to the diaphragm. His words, amplified, rolled out through the cavern in the Ancient Tongue.

"Yes--the gods return! Summon the Zarno! Let none fail to obey the summons!"

Shouts went up. The Zarno whirled and raced away. For the moment, Garth was alone.

He concentrated on the transmitter again, commanding the robot to move forward to the edge of the dais, till he could see its back.

"Raise your arm. Step back. Forward again. Back."

It worked. The robot obeyed his mental commands, awkwardly, but--it obeyed.

"Back. Sit on the throne."

A jarring crash deafened Garth momentarily. He had forgotten how huge the robot was. No doubt the creature should lever itself down gradually into its seat, instead of dropping a ton of metal solidly on the black block.

Footsteps again. The Zarno were beginning to pour into the cavern. Huge as it was, they almost filled it. They flung themselves flat, crawling toward the dais, nodding their misshapen heads in awkward rhythm. Their voices were raised in a deep-throated chant.

Garth concentrated. At his mental command, the robot rose and paced slowly forward.

"_Kra-enlar!_"

Garth put his mouth to the diaphragm. His voice crashed out.

"The gods have returned! Hear me, O Zarno!"

"_We hear!_"

"Let no Zarno fail to come to the temple of the gods. Have the guards left their posts?"

"_Nay--nay!_"

"Summon them," Garth roared. "When the gods speak, all must hearken. Let every Zarno come to me now, or die!"

Some of the creatures raced away and returned with others. The chant continued.

"Have any Zarno failed to heed my summons?"

"_None--none! We are here--all!_"

Garth nearly shouted with relief. There were almost two thousand Zarno in the cavern, he judged, all genuflecting before the dais. And that meant that the city was unguarded--that Doc Willard could lead the others to the antigravity hangar.

If he could hold the Zarno here!

Garth shook his head, feeling oddly dizzy. He tried to concentrate. At his mental order, the giant robot lifted its arms in symbolic, ritualistic gestures he remembered from the tripod-recorder.

But the dizziness persisted. Garth realized that his lungs were hurting. He found it difficult to draw a deep breath.

Air--he needed fresh air! The inhuman lungs of the Ancients probably were able to endure lack of oxygen far better than the human organism. In any case--Garth realized that the air was getting stale.

He investigated the vision-slit. It was barred by a glassy, transparent pane that seemed as hard as steel. Well, it would be necessary to open the panel behind him--a few inches, anyway. Garth's hand sought for the spring. It was in plain sight; there was no need to conceal it within the throne's compartment.

He pressed it. There was a low grinding that stopped almost immediately. Garth tried again.

Useless. The mechanism, somehow, was jammed. Probably its mechanism had failed when the huge robot had crashed down on the throne.

That meant--

Garth's fingers tried to find some purchase on the smooth surface of the panel. He failed....

A Zarno called a question. Garth turned back to the eye-slit, trying to fight back his dizziness. Heads were lifted, he saw, watching him inquiringly, as though the silicate creatures expected something. Well--

He made the robot move again, its arms reaching out in ancient ceremonial gestures. A gasp of awe came from the Zarno.

Their chant thundered out, deeper, sonorous and inhuman.

* * * * *

Garth felt the beginning of a throbbing ache in his temples. He was trapped here. How long could he stand it? He was human, not one of the Ancients. He needed air--

He held the Zarno, but not for long. Once more bulbous heads were lifted, oval eyes watching him inquiringly. They were expecting something--what? Garth tried to remember what he had seen in the recorder.

More heads were lifted.

Garth made the robot step forward, raising its metal arms. He had to say something--anything that would hold the Zarno quiet for a while, long enough for Doc and the others to escape. Words he had forgotten since childhood came suddenly unexpectedly to him. The English phrases meant nothing to the Zarno, but the sonorous, powerful chant kept them silent.