LUNAR STATION

Bill Bonwitt, the young chief engineer at the mercury mines that bored into the surface of Earth's moon at the crater Tycho, knew something was wrong. His hob-nailed boots beat a swift tattoo on the metal steps as he quick-footed down to the radio room.

"Crane!" he yelled to the operator. "Have you felt it?"

His friend grinned up from the ethertype machine. There came a quivering of the floor, then a prolonged but diminishing vibration. "I felt it, sure. That was the transport, blasting away from Tycho, is all. What's wrong with you—jitters?"

"Nuts, Crane; it wasn't the ship. We're moving; the moon's on a rampage. Earth's gone cockeyed overhead. I've seen it, felt it."

"Wha-a-at!" Crane's grin froze. He slanted his sorrel-topped head. "Damned if I don't think you've got something there," he conceded after a moment. "I feel it, too; sort of a swing and sway."

The operator attacked his keyboard. Tape chattered through the transmitter wildly. "Asking New York to check with Mount Palomar," he explained soberly. Val Crane's freckles emerged from their camouflage as his cheeks paled. The moon had gone haywire.

"Come up above," urged Bonwitt. "In the dome you can see—"

"Right," Crane approved, switching off his transmitter as the tape snipped out, his message completed.

The beryllium steps resounded again as two pairs of heavy Lunar boots clattered upward. Black velvet of the heavens loomed above the blacker braces of the crystal dome breaking the scene into an intricate network. Earth, a huge ball overhead, was swinging across space, when it should have been stationary.

"Cripes!" swore Crane. "What the—"

Luna quaked mightily and Earth slowly swung back to normal with a snap that jarred their insides almost loose.

Stunned, breathless, they ducked as the Atomic I blazed away from the base of Tycho's rim, her twin jets spouting trails of blazing magnificence in a double arcing trail earthward. A dazzling sight under ordinary circumstances, inconsequential now.

A furious chattering of the ethertype below sent them to the room of the radio with more echoing thumpings.

Crane grabbed the tape, reading aloud as it fluttered through his trembling fingers. "Mount Palomar reports Luna shifted three and one half degrees eastward from normal by unaccountable rotation on her axis, returning suddenly to original position. More later from here. Keep us advised of any further developments there. Atomic, N.Y."

"Three and a half degrees!" gasped Bonwitt. "Sixty-six surface miles in as many seconds."

Sounds of distress wafted up from still further down in the workings. A metallic crash. Shouts. Bonwitt started down toward the machine shop as Crane hunched once more over his ticker.

A new drill press, not yet bolted down, had toppled and pinned one of the mechanics to the floor. The man was unconscious; his fellow workers were heaving sweatily to free him. Peterson, the new super of the mines, looked on, bellowing, purpled. He leered at Bill Bonwitt.

"What the hell happened?" he demanded. "Where were you?"

Bonwitt flared up; he didn't like Peterson. "I'm off duty," he snapped. "Besides, nothing could be done. All that happened is the moon shifted a little on its axis and came back."

"I'll say it shifted! A mile of Tycho's rim caved in just past our workings. And you in the dome!" A sneer twisted the super's thin lips. He was looking for trouble.

Bonwitt bristled anew but curbed his wrath, shrugging it all off.

"No damage, was there?" he inquired mildly. "No air leaks?" He moved nonchalantly to where they were helping the victim of the accident.

Peterson followed, watching as they pulled the man out and laid him on a bench. Bonwitt examined the injured man swiftly.

"No broken bones," he proclaimed tersely. "Take him to Doc Tonge. He'll fix him up in a jif."

The fellow, tawny of skin, a runt of unguessable age and origin, gasped and opened his eyes. They fixed, glass-hard, on Peterson.

"Ficora!" he shrieked. "Jombalo!" He slipped again into coma.

Bonwitt wheeled but Peterson had gone. Queer! Andy Pauchek was the victim's name on the payroll. A mystery to the rest in the place. No friends; apparently no antecedents. But it was sure he had known the new super before and held something against him. Hated him.

Bonwitt climbed the stair to consult with Crane.

The ethertype told them little they did not know. A few Lunar crags and spires had toppled; crater rims had crumpled. But Earth astronomers had no explanation and were themselves mystified. New York headquarters of Atomic Power didn't care as long as their workings weren't wrecked. So that was that. Crane was disgusted.

Bonwitt told him about Peterson.

"Screwy," the ethertype man agreed. "Couple of times he's wanted to sneak out messages in private code. 'Can't do; regulations,' says I." Bonwitt chuckled mirthlessly. "Where'd he want to ethertype?"

"Another odd thing; I don't know."

"What do you mean, you don't know? No address?"

"Just an off-wave call number. X2273—not listed." Crane yawned.

"The crook!" exploded the young Chief. "Got to snag him."

"I've been trying to. Thought you'd get wise soon, Bill."

Bonwitt frowned. "No copies of his messages?"

"Naturally not." Crane lowered his voice. "He got them through."

Amazed, the engineer asked: "How?"

"Gates." Gates was the relief operator at the ethertype.

"Lord! Maybe you're right."

"Sh-h!" Crane warned. "Gates is due any minute."

"So what's any of this to do with Luna going haywire?" asked Bill thoughtfully. "If I thought—"

"Let's talk about it tomorrow," whispered Crane as footsteps neared.

Gates came in, sleepy-eyed, sullen. He ignored them both.

"Going to turn in," Crane winked at Bonwitt. "Sleepy. Bye."

"Me, too," grinned the engineer.

But he went up to the dome and mulled things over for hours.

Bonwitt couldn't connect the moon's eccentric behavior with Peterson's. But something was up. If personal, okay; if against Atomic Power, something else again. Looking out first over the moon's broken desolate surface, then up at the bright orb of Earth, the engineer tried to rationalize things.

It couldn't be against Atomic. Mercury is something you just can't steal. It's heavy. Atomic is the only big market for it. You can't make big-time power on Earth without mercury, and Atomic has the monopoly. You have to have a fleet of space ships to transport it—and a market.

No; something bigger was involved; something simpler.

Peterson. What was he up to? He had long been a trusted man in various departments of Atomic. Where did Gates fit? The engineer began thinking over his own ten years with the Company.

Three years on Luna. Rotten. But you have to mine mercury for the terrestrial power plants. The moon was the only place. Lucky for Earth, in 2012, when mercury deposits petered out in Rhodesia, the first rocket to the moon found that Luna's rays were mostly of purest hydrargyrum. Pure metallic mercury, frozen solid in the long Lunar night, liquid in the equally long day.

And, fortunate for Atomic Power, World Government had granted them exclusive rights to its mining.

But you couldn't fit Peterson into any of this. What could he do to the immensely influential Atomic Corporation? Or to Luna? Bill Bonwitt gave it up and went to bed. It was just midnight (Lunar) and only fourteen more days until sunup. Dozing off comfortably, Bonwitt wished he could sleep that long.

The ethertype man awakened him a few hours later. "Wake up, Chief," he husked, shaking, his teeth a-chatter.

Blinking, Bonwitt sat up. "What the hell? What time is it?"

He was climbing into his clothes in a mental hangover of dreams.

"Six. It'd be daylight back home. That mechanic, Pauchek, is dead. Knife in his throat. Peterson's gone. So's Gates."

Now Bonwitt was thoroughly awake. "So!" he grunted, tying his last lace. "We go hunting."

"Right." Crane looked out at the bleak lunar landscape through Bonwitt's dome. Earthlit, that landscape. Cold. Airless.

Bonwitt shivered, looking over at Peterson's dome across the long transverse passage of the workings. "Where the hell are they?" he asked.

Crane said suddenly: "Look, Chief. See what I see? Two shadows out by the crater wall? Moving."

"I do—so help me! Space-suits, both of them. What—?"

The earthlight on Luna, thirteen times that of moonlight on the earth, showed up the men clearly. One was carrying a tripod. This he set up in a moment, swung a tube on its tip skyward—earthward. The tube began spouting vivid white flame in spurts.

"Code!" shouted Crane. "Continental. But in those five-letter combinations. They're signalling eastern Asia!"

"Come on," husked Bonwitt. "We're going to search Peterson's hangout." They scudded to the other dome.

Crane stood guard while Bonwitt searched with a flash. Outside, the signalling continued interminably. The engineer found nothing.

"They're starting back," Crane warned.

But they weren't heading here; those space-suited figures sped in the direction of the air-locked hangars of the small lunar ships.

"After them!" gritted Bonwitt. "This is the pay-off."

He and Crane whirlwinded through refinery and undersurface tubes to the hangar. Got there just as the inner seal was opening. They crouched in the shadow of a local ship. A space-suited figure parked the signalling instrument and yanked off its flexglass helmet. Gates, Peterson, too, removed his helmet.

"Now for the other side," rasped the super, diving toward one of the smooth-hulled local ships. "This the one?"

"Yes. She's all set."

"Good." Peterson climbed through the entrance port.

Both men were inside and the port closed behind them.

"Come on, Crane," whispered the engineer.

They took the ship that had hidden them in its shadows. Bonwitt knew these little skimmers. Their control was simple, their gravity propulsion just the ticket here where the down-pull was only a sixth of Terra's.

"Damn!" growled Bill. "They've five minutes' start. We have to wait till they're through the lock."

Crane said confidently: "We'll snatch 'em."

The other ship taxied to the airlock and was quickly inside. The inner door swung home. The wait seemed interminable.

Then the inner door swung back. Bonwitt juggled the magnetic remote control. They were inside. Through. And, in a moment, on the airless surface of Luna. Above, high over Tycho's vast wall, was the gleaming, torpedo-shaped hull of the super's ship. Bill went hot after it, more than ever puzzled as to what was going on.

The other side, Peterson had said. That would mean the opposite side of Luna—never seen from Earth.

Directly toward Luna's south pole and flying high, went Peterson's ship. Bonwitt drove after him. At this speed they'd soon pass the terminator and be in sunlight.

"No sense to any of it," Crane was saying. "Nothing much different on the other side than this side. What can they do around here?"

"So says me," agreed Bonwitt. "Anyway—a hope—we'll learn."

"There's the terminator ahead," chirped Crane. "Sun glasses!"

Dark lenses were quickly donned. Tall peaks ahead burst into blazing pinpoints, their blinding splendor deepening the shadows beyond the on-rushing terminator to Stygian inkiness. Dazzling white crawled down the nearing spires and suddenly the sun's corona smote them like a blow with its glory. Abruptly they were in vivid sunlight.

Peterson's ship still sped on before them. One hour; two; three.

Crane chuckled: "Hell to pay if N.Y. is trying to raise Gates."

"He's through," Bonwitt returned easily. "Fired; I'll bet."

"Me, too. But, sa-ay! Look at that!" Crane flung up his arms against a glare that blazed suddenly through the forward ports.

Directly ahead was a broad flat crater that shimmered in the sun's unobscured rays like a gigantic mirror of polished silver.

"Mercury!" gasped Bonwitt. "A lake of mercury ten miles across. No one's ever reported that ."

"I'll bet Peterson knew about it. Look, he's circling."

It was so. The engineer flung his little ship off toward the east to avoid detection. They speeded out of the sun's reflection from that lake of mercury. Its unrippled surface rose rapidly off starboard and was blotted out by the crater wall that enclosed it.

Then the leading ship had landed. Bonwitt maneuvered to land in the shadow of a huge boulder. Clambering into their space-suits, they jumped the twelve feet to the powdery footing underneath. As easily as they'd have dropped two feet in earth gravity.

Space-suited likewise, Peterson and Gates ducked into the dark opening of a cavern mouth. Bonwitt and Crane sneaked after them. Inside the cave entrance was instant, utter blackness.

"Crane, where are you?" the engineer asked softly. For reply there came a crash as of the pinnacle of Proclus toppling on his helmet and a swirling burst of stars such as had never graced the firmament.

After that, Bonwitt slipped into blackness.

He awoke with splitting head and a red film before his eyes. Two blurred figures were bending over him. He examined an egg-sized bump on his head with languidly exploring fingers. His helmet was off. The figures were those of Crane and Peterson. Damn! Bonwitt sat up jerkily and the effort set his head swimming and throbbing.

The super was grinning his sardonic grin; Crane was grimacing a warning. "They've got us, old man," he said. "Might as well make the best of it. Here, let me help you up."

With his aid, the engineer rose up and stood groggily swaying. Peterson, legs wide, bristly brows close, sneered at the big Earthman.

"What'd you hit me with, a tractor? Or was it a meteor that fell?" grunted Bonwitt, gingerly fingering the lump on his head.

Peterson's sneer relaxed. "Now you're using sense," he approved. "If you'da come up fighting it'da been just too bad for you."

The engineer spied a curiously shaped weapon in Peterson's belt. Entirely unfamiliar but looking mighty dangerous with its ugly flaring snout and the cooling discs along its stubby barrel.

"All right," said the super. "Your side-kick'll tell you more about things here. Play ball and you're okay. We may even find jobs for the two of you. But no monkey business."

The man turned on his heel and disappeared through the arched door. Bonwitt saw they were in a circular chamber lined with bluish metal. His gray eyes questioned Crane.

"They jumped me and tied me in a knot," the ethertype man explained. "Gates slammed you down, the rat!"

"How long was I out?"

"An hour or so. And you won't believe what you see here. Can you walk now?"

Bonwitt took an experimental step. "Sure."

"Come on then." Crane started for the doorway.

"We're not locked up? Not guarded?"

"No, but prisoners all the same. In the damndest place. Wait."

They came out on a balcony that limned a seemingly bottomless pit with a huge vertical shaft that dropped centrally from high above and vanished in the depths below.

"What in hell is it?" demanded Bonwitt.

"You haven't seen anything yet." Crane moved to the cage of a lift.

"Cripes! An elevator on the moon!" None of it made sense to Bill Bonwitt.

"We sure stumbled into something, Chief," agreed Crane.

As they dropped sickeningly in the cage, the engineer saw that the controls of the automatic elevator were of craftsmanship like none he had ever seen.

Crane said: "I don't understand it, either. They didn't tell me much, but kept me with them till Gates had landed below. I saw enough to scare the devil out of me, though."

"Why do you suppose they didn't knock us off like they did Andy Pauchek?" wondered Bonwitt.

"They want us to join up with them. At least Peterson does. Gates would cut our throats in a minute."

"M-mm. He's tough. Let's see; he came on the job a month before Peterson, didn't he?"

"Right, Chief. And they were thick as thieves from the start."

"Don't we ever reach the bottom?" asked Bonwitt impatiently.

"It's a long way down but we're nearly there." Crane puckered his sandy brows. "Nobody can make cables that long," he opined.

Bonwitt examined the controls again. "It's a gravity lift," he decided. "Nothing like it on Earth. Suppose Peterson's found an underground civilization here?"

The ethertype man grinned. "I knew you'd get it. Peterson told me or I'd never have guessed. Until I saw the damn creatures."

"You did see them?"

"Hundreds. They're queer—like Pauchek."

"So-o. That explains a lot. Peterson's been here before, often. I still don't get it about Pauchek, though."

The lift slowed down and stopped. Crane led the way out onto a second balcony, a gigantic sweeping curve of it.

They were in a vast hollowed-out space. An inner world within the moon! Damply warm and redolent of life. Its vastness stretched off into the distance, beyond sight. Most amazing was its source of light, an enormous green-white globe that loomed in the near distance. A cold but luminous sun within the moon!

"It's real," chuckled Crane, watching Bonwitt.

Below them was a wider balcony, a ledge on which were ordered rows of great machines with naked little brown men scurrying in their midst.

To the right was the great grandad of all of those machines, a huge drum-like affair with tapered helices at crazy angles and with the big steel shaft they'd seen up above projecting from its vertical upper bearing and vanishing through the bore in the rock overhead.

"Lord!" gasped Bonwitt. "A motor! What can it drive?"

"You'll soon learn," said an oily voice at his shoulder.

The engineer wheeled to stare into Peterson's close-set, glittering eyes. Gates, saturnine, contemptuous, was with him.

"You go to Don Peel right away," the super told Bonwitt. "Crane goes with Gates. To see our ethertype."

"But—" Crane started to object.

"You'll go with Gates." Peterson fingered his strange weapon.

The two ethertype operators disappeared into a passage mouth.

"Who's Don Peel?" asked Bonwitt.

"The king—Gosak, they call him—a simpleton whom I've taught a little English. He's in the palm of my hand, though I handle him with gloves. I want you to play up to him."

"Suppose I don't. Suppose I warn him?"

"You won't." Peterson carelessly sighted his curious weapon on a rock ledge in the passageway. The thing bucked to a screaming hiss that belched from its snout. No more than that, but the rock spurted incandescence and puffed out of existence. "No, you won't shoot your mouth off, Bonwitt."

"What's the idea?" growled the engineer. "What're you up to?"

"All in good time, my boy. Here we are; remember what I said."

They entered a small, softly lighted room. Two wizened, breech-clouted men bowed to the super and he jabbered unintelligible words. An inner door opened and the two Earthmen went through.

"Bonji, Don Peel. Bonji, Gosak," the super mouthed, spreading his pudgy hands and salaaming before a turbaned brown man squatted in the center of a waist-high circular table that surrounded him.

"Bonji," this one replied gravely. "This new helper?"

"Yes, Don, this is Bonwitt. Crane's with Gates."

The little brown man looked out keenly from under overhanging brows, eyes gleaming like a cobra's. "You sure we can trust?"

Peterson nodded with assurance.

Don Peel bared momentarily a mouthful of yellow fangs between lips that writhed hideously. Bonwitt's stomach went sick.

"Good; you fix." The Gosak dismissed them with a scrawny hand.

"Had to do that," the erstwhile super explained in the outer passage, "to keep him happy. Or his men'd be taking pot shots at you."

"That would be nice. They probably will anyway."

"No, no. Everything's hunky-dory now, so long as you co-operate. We go to my hangout now and I'll give you the dope."

So cocksure was the man that Bonwitt's ire rose dangerously. He controlled himself with an effort. He'd have to find out what was what, pretend compliance with any plan, and—wait.

Peterson's hangout, as he had termed it, was a drafting room and office combined. The desk and drawing table were of curious Lunar construction. There were a few chairs and a filing cabinet. Maps and drawings on the walls. Maps of Earth and Luna; drawings of queer machines and structures. One was a cross-section of the moon as Bonwitt was beginning to know it existed. The core, the inner sun, was not central, he saw.

"Look, Bill." Peterson poked a thick finger at this drawing. "Here's where we are; four hundred miles under the crater called Nemesis."

"Four hundred—" Bonwitt gaped, seeing the vertical shaft on the drawing, piercing its way upward through tunnel and many bearings to the surface, "—impossible!"

"So I thought in the beginning. But much is possible here. That shaft, for instance. The Selenites have its weight almost completely nullified with anti-gravity forces. They know something, the devils."

"But the sun, or whatever it is, isn't pictured central. In fact, it seems to contact one side of the moon's central cavity."

"Naturally. That's why the same face of Luna is always towards Earth; it's on the heavy side, of course. Here, sit down, Bill."

Peterson indicated a chair, which Bonwitt took. "And," continued the ex-super, "that sun, as you call it and as it properly is, can be shifted from normal position. That's what was done last night; that's why Luna shifted on her axis. A test. I knew, of course, but pretended ignorance back on the other side. Now you're in it, I can tell you.

"The brown men are native to the moon but not to our solar system. Their ancestors inhabited the body's surface when it had an atmosphere and was warm in the light of a distant sun. They burrowed when they learned their planet was to be hurled into space by a cataclysm which was to break up its solar system. And when, in the distant past, their world was captured by ours as a satellite, they had to remain beneath the surface. They burrowed deeper, found this inner realm, this world within a world. The inner sun then was still quite hot; it yet holds nearly enough heat for their comfort and sustenance.

"Through countless ages, this race has been dissatisfied. They wanted to live outside as did their forbears, but could only go to the surface in space-suits. They began planning a migration to Earth. The huge motor, the shaft, the crater, are the results. The means."

"To migrate?" Bonwitt was incredulous.

"Yes."

"Peaceful, or warlike, this migration?"

"They plan peace if possible, war if necessary."

"And you—where do you fit in? Are you one of these guys who wants to save our world?"

"Stop it; stop it—until you know. You see, the mercury-filled crater above is to become a great mirror for reflecting sunlight earthward. Along the resultant light beam the Selenites plan to travel in cars which are propelled in concentrated photon streams—"

" Wait a minute," the engineer interrupted. "The crater faces away from Earth."

Peterson grinned anew. "Now it does, yes. But the moon will be turned around until it faces Earth."

"Turned a- round !"

"Just that. That's the why of last night's test. The sun inside here is to be shifted by projected forces until the center of gravity of the moon's total mass is at the proper focus. Then the shell turns over until the crater Gates called Nemesis is in the right position. By now the motor spins the mercury until centrifugal force reverses the natural convexity and the ten mile vat of mercury becomes a big concave mirror.

"The reflected light beam can be narrowed down to any desired size by changing the concavity—altering the motor speed. Just by shifting Luna's inner sun."

"Why," gasped Bonwitt, "if all the sun's heat over a ten mile diameter mirror were focussed on a spot say one mile in diameter on our Earth, one hundred times normal sun energy would be concentrated in this area. Anything would be instantly consumed."

"You've hit the nail on the head," said Peterson. " One nail. That's Gates's nail, which I intend to pull out. But the Lunarians plan only to make a plane mirror of the mercury crater, which would not overheat anything on Earth but only provide a lane through which their photon cars can pass. They believe they can effect a peaceful colonization."

"What do you mean, Gates's nail?" Bonwitt's lips set grimly.

"World conquest! Worse—revenge. He intends to blast all big cities to ruin, then resume the dictatorship that was once his father's."

"His father's?" Memory came to the young engineer of history. Establishment of the World Government in 1975. Exiling a man who had set himself up as World Dictator. Yes, his name had been Gates. He had died in Siberia. And this Gates was the son—explaining the signalling to Earth. A party of adherents waited there for a millennium or something. "But you helped with his signals," Bonwitt accused.

"I did," grinned the older man, "to keep this screwball's gang together where I can blast them out of existence as soon as I get Gates. Gates discovered inner Luna and, the fool, told me about it. Played right into my hands."

Bonwitt shuddered. Here was a double-crosser of the first water. "How do you plan to upset the beans and where do you profit yourself?" he asked.

"I'll kill off the Selenites—there's only a million or so—with a supersonic generator Gates developed. Their brains are susceptible to a certain vibration rate; they'll die like flies. And Gates won't be here to interfere. There'll be no more Selenites; I'll dictate to Earth. I'll blast some forests and a couple of villages to show them I can do it. Perfect, isn't it?"

The engineer stared. Peterson was a madman, a wholesale killer at heart—worse. "What would be your terms?" Bonwitt asked steadily.

"Not harsh. I don't want to be a dictator nor to destroy cities. I hate politics and war both. But I'll control Earth just the same—with wealth and power. I'll demand personal title to the moon and to Atomic's two space ships. To the larger ship for distant planet exploration now under construction as well. Also a billion dollars in gold delivered to me here on Luna. With these advantages, I can do anything I want to. Care to join me or not?"

Mad, totally mad, this scheme of Peterson's. But just mad enough to come near succeeding unless he were stopped. The world would, in panic, concede anything if ever he should get as far as turning over the moon and burning forests and villages. For that matter, his madness might then flare up to the point of wreaking wholesale destruction as Gates proposed and intended. Bonwitt would have to play for time.

"Sure, I'll join up," he lied. "Who wouldn't?"

Peterson smiled paternally. "Right; who wouldn't? And once I get control, see how many more will join up. Beats working for Atomic, doesn't it?"

Bonwitt nodded dully. Fantastic as the thing was, the engineer recognized the danger to Crane and himself. The world could take care of itself. But the Selenites? Here were Gates and Peterson both plotting their destruction. For all Bonwitt knew, Gates might be planning the same thing against Peterson. If either won out it would be bad for a certain engineer and an ethertype man. Maybe—

"I'd like to see your ethertype myself," he told Peterson. "It's the one you used to communicate with Peel from the workings, isn't it?"

"Huh? How'd you know that?" The super tensed suspiciously, then relaxed. "Oh, Crane guessed, I suppose. Sure, you can see it. Follow me."

When they reached the ethertype room, it was to see Gates, wild of eye and disheveled of clothing, standing over Crane with one of the odd pistols in his hand. Crane's head was missing—blasted away. With a screech of pure animal fury, Bonwitt dived at the killer. Off guard, the big ethertype man went down and his pistol clattered into a corner. But he was up in a flash and the engineer was in for a battle.

He ducked too late and took a right to his temple that set him spinning and seeing stars. A left cross spun him back and, by enraging him, cleared his head. He clinched to get breath, then flung the big radio man off and drove him against the table. Gates staggered and hung on under a rain of body blows, rallied to come back with a left and a right that both jolted Bonwitt's jaw. Then he was tearing at the engineer's eyes with clawed fingers, bearing him to the floor.

So it was to be that kind of fighting! Bonwitt heaved up and got a full Nelson on his wriggling foe that nearly snapped his spine. He downed Gates, panting, cursing between his teeth. He could see Crane's poor headless body sprawled there. The sight robbed him of all knowledge of what he was doing and he did not return to normal until the voice of Peterson halted him. Only then did he realize that he had been banging Gates's head against the metal floor with all the force of a pounding sledge.

"He's dead," gloated Peterson. "Save your strength."

Bonwitt saw that it was true. His antagonist's skull was a thing squashed, unrecognizable. Sick at the stomach, he reeled to his feet.

Peterson stood regarding him with a cryptic smile, a pistol in either hand, his own and Gates's. "Good work," he approved. "Saved me trouble. But we'll have to get rid of the bodies. Have to tell Peel I've sent the two to the workings temporarily."

He eyed the panting engineer sharply and was apparently satisfied, for he thrust the two pistols in his belt. But he wasn't taking any chances with the powerful and alert Bonwitt; he'd been quick to snatch that second pistol out of reach during the fight.

The succeeding days were nightmares of uncertainty to Bonwitt. Under Peterson's eye constantly, no way of getting the upper hand over the man occurred to him. And, could he have done that, he'd still have the Selenites to account to. Besides, even if he could remove Peterson and get himself away, there was little time left in which to do it. It was self-preservation now.

The big geared down motor was already starting to churn the mercury in the crater above into rotation. Its starting torque must be terrific to get that huge mass of metal in motion. Even to think of so enormous a disc, liquid or solid, in rotation was staggering; the speed must be not in revolutions per minute but a fraction of one turn in that terrestrial measure of time. For, even at one revolution per minute, the peripheral speed of the mass would be 31.416 miles a minute. Not only an impossible figure but far in excess of that needed.

Time fled on wings. Bonwitt did his best to locate the supersonic wave generator. If he could find this and warn Peel he might circumvent Peterson and perhaps earn from the brown men a gratitude that would pave the way for Earth's acceptance of them as colonists.

The more he contacted them the more he liked the little brown folk and the more he sympathized with their wish to get to the good green Earth. Essentially harmless, they were most admirable in their manner of living and considerate in their relations one to the other.

Undoubtedly, New York had long since known of the absence of four important men from the Lunar workings. By now, quite likely, they had sent over one of the transports to learn what was wrong. But nothing could be done from there; they didn't even know of inner Luna.

Bonwitt's nerves drew tautly near the breaking point. Peterson was waiting until the last minute to loose his supersonic vibrations on the unsuspecting brown folk. He'd have to wait till the moon had turned over and the beam of reflected sunlight was directed earthward. For the huge machines necessary to these important preliminaries needed many men in their operation. After that, these men could be dispensed with. One man could operate the final controls; one could blast out an entire city if he wished; one could operate the ethertype and make terms. Two were better; perhaps that was why Bonwitt was still alive.

All too quickly came the day. Huge machines hummed and groaned. The great gelid sun began to roll slowly over the inner surface of the satellite. The outer shell of the moon started rotating. Luna was turning over. The great mirror of liquid metal above was revolving at precisely the speed to produce a plane surface, astronomically plane.

Peel was at the final control with Peterson beside him, watching the viewing plate. Bonwitt was there, too. Peel's customary two guards.... The engineer hadn't had time to find the supersonic wave generator. How could Peterson get away to activate it? Bill's eyes dropped accidentally to the man's feet, one of which was edging toward the base of the control pedestal. A hidden button was there; this wholesale murder was to be accomplished by remote control!

On the vision plate, Earth swung into view. The hitherto unseen side of the moon was facing it. What a furore must be upsetting both amateur and professional astronomers at home! Only a thin crescent was Earth now, with a vast dim area lighted only by moonlight from here.

Soon there'd be a brilliant circle up there, a circle ten miles in diameter, sharp against the near-blackness. And, if Peterson won, it would close in gradually until there would be a searing, blazing speck consuming everything within its one mile circle. Not if Bonwitt could stop it. The super's foot, he saw, was nearing the secret button.

The sense of swaying motion ceased; the moon once more was still, ominously so. Earth rushed forward in the viewplate as the magnification of the radio telescope was multiplied. Peel depressed a lever and, in slightly more than a second of time, there flashed a circle of sunlight that enclosed nighttime New York City and its environs. What a panic this must be starting! Peterson's foot moved suddenly. In the same instant, Bonwitt flung himself upon him, slamming him to the floor.

Peterson's foot slipped suddenly. In the same instant Bonwitt flung forward, slamming him to the floor.

"Peel! Peel!" he yelped, fighting to keep the maniac's hands from his pistols. "He'll kill you all. Believe me, Peel!"

Then, amazingly, there was the screaming hiss of a lunar weapon. Peterson's head exploded almost in his face with brilliant pyrotechnics. Peel had killed the man and was standing there grinning in a most friendly manner, pistol holstered, waiting for the engineer to rise.

"Thanks, good friend," Peel was saying. "We knew he traitor but not find machine. Pauchek learn some but not know all. You fix."

That explained the incident of the unfortunate machinist. Bonwitt could only goggle at the Gosak of inner Luna as he rose to face him.

"You fix," repeated the little brown ruler. "You keep my people safe. Now we ready to talk your people. We go help they. They help we. Not?"