A faint quiver ran through the great hull of the rocket ship, and passed. The harsh drumming of her motors died to a singing drone. Flight-Commander Bruce Ross nodded absently. The ship had shaken off the Earth-drag, and the speed indicator climbed fast. Eleven, twelve hundred miles an hour, the flagship of the rocket-ship fleet sped on its way to the Moon.

He moved to the forward telescope at the side of the control cabin and squinted at their objective. The pale circular bulk of the Moon loomed larger than when he had last observed it. He twisted to look through the rear telescope, and saw with satisfaction that the other seven ships of his fleet were following in echelon, each a mile and somewhat to the right of the one before it.

Ross grinned with pleasure. It wasn't his first trip to the Moon, but on that earlier occasion, when Magnus, King of the Moon People, had pledged a truce with the Earth's Council of Seven, he had commanded only the flagship. Now he had his own flagship, larger and more powerful than that outmoded rocket ship of five years ago, and seven more fighting ships besides. He strolled over to stand behind his navigator, plump, bespectacled Harrell Moore, who was squinting strainedly through the star-scope.

"How are the stars behaving, Harry?"

Moore's forehead was corrugated with concern. Without taking his eye from the scope he muttered softly, "Something funny going on, Bruce."

He moved back to let his chief step to the eye-piece. But before the flight-commander could take the seat a sliding door opened with a bang. The two turned, startled.

In the opening swayed a white-faced clerk. "Sir," he gasped, "there's trouble with communications!"

"Well?" snapped Ross.

The clerk brushed sweat off his brow. "The ray-type machine's gone dead, sir, and the ray-phone's crippled. We get only a weak muffled voice from the Council of Seven Headquarters!"

"How about the blinkers from the other ships?" snapped Ross.

"Blinkers are working, sir—" The clerk stopped short as Ross jumped to the rear of the control room.

"Jorgens!" snapped Ross. "Signal each ship, and ask if they've—they can get Seven Headquarters on the ray-type!"

"Aye, sir!" The signal chief hastened to the blinker buttons and began to rap out the message. He was half through it when a dull boom echoed like a sigh through the control room.

Ross and Moore exchanged startled glances. Jorgens, white of face, looked up, his hand poised as if paralyzed over the buttons. Then Ross jumped to the rear telescope, which commanded a view of his following seven ships.

There were only six. Where the seventh—the last in the staggered-line—should have been, a faint glow filled the air. Ross stared at it, heart-sick. Was that blow the last sign of his rear guard? A rocket ship blotted out—destroyed! But how? How?

"Jorgens!" he snapped. "You had the Moon on the ray-type a while ago! Try to get that Peak One station again!"

"Aye, sir," breathed Jorgens shakily. He tapped the black key, rattling the call signal feverishly, then snapped on the receiver. The prong-like type fingers made no move.

"The ray-phone!" rasped Ross.

The signal chief plugged the yellow cylinder into its gray socket, and flashed the light beside it. "First Fleet, calling Peak One!" he chanted. "Peak One, answer First Earth Fleet!"

Ross, Moore and Jorgens held their breath. No sound came through the ray-phone trumpet. Jorgens lifted a gray face toward Ross.

The fleet commander smiled wryly. "Let it go, Jorgens. Check all the batteries and connections before you try again."

As Jorgens nodded and disappeared to trail the snaky coils of insulated ray-tubes to their battery reserves, Ross turned to Moore. "Number Eight's gone," he said softly.

Moore blinked. "Gone? Where?"

"Where the woodbine twineth," said Ross.

Moore's breath came faster. "Wiped out?" He whipped off his spectacles and polished them absently, his jaw working on his half-forgotten chew of tobacco. "Gone," he muttered dazedly.

A sudden thought struck Ross. He gripped his navigator's shoulder. "The stars! You said there was something funny going on!"

Moore's eyes flashed. "Yes!" He slapped his glasses on. "Come on! Let me show you!" He led the way to the star-scope.

Ross, following, stopped as a signalman approached with a typed message—the answer to the blinker call that Jorgens had started. The first sentence was short and blunt. "Number Two reports ray-type dead, ray-phone weak." Messages from the other five ships were identical except in the case of Number Seven. An added sentence from the last ship of the line stood out on the page and Ross felt sick inside as he read it. "Number Seven also reports explosion on right quarter where Number Eight was flying. No sign of Number Eight."

At the star-scope Moore hovered as Ross applied his eye to the powerful lens. "That's Denabola you're on." The navigator's jaw worked, his eyes glittering.

"Dim," muttered Ross. "Clouds?"

"No!" exploded Moore. "Denabola was bright as ever, then suddenly went dim!"

Ross sat up quickly, a question in his staring eyes.

"You mean—the way the red stars go dim when we drain them of the red rays that power our ships and inter-planet communications?"

"Just that way," said Moore, blinking in excitement.

For a long moment their glances were locked. Then Ross heaved a stifled sigh. "This may mean a lot, Harry," he murmured. "I wonder if it might not even mean—"

"Whatever happened to Number Eight?" asked Moore quickly.

Slowly Ross nodded. "Let's see. Denabola's a blue star. Have you checked on any other blue stars?"

Moore took the seat at the star scope. "Only Vega. She's dim, too. Let me get Sirius." He twirled a knob at the side of the telescope barrel, then another, then straightened, with an explosive gasp. "Look at Sirius!"

Ross looked and caught his breath. Sirius, the brightest star in all the firmament, was a dull lackluster thing.

Flight-Commander Bruce Ross sat back at the star-scope and pushed his space helmet off his head. He ran a steady hand through his unruly blond hair, smoothing out the tight wrinkles in his broad forehead as if to silence the urgent question that hammered in his brain. Something was happening in the heavens, and all his lore of flying and fighting might be none too much to set against the celestial puzzle.

"Harry," he asked finally, "the Moon Men know all about our red-ray work. Do you suppose they've gone to work somehow on the blue stars?"

Moore screwed up his face, blinking behind his glasses. "Well," he said finally, "there's Horta."

Ross nodded. "I was thinking of Horta," he admitted grimly. He had never forgotten Horta, Lord of the Moon Caverns, the darkly hostile savant who had held out so long at that fateful conference when the Council of Seven, rulers of the Earth, had made their all-or-nothing flight to the Moon, there to lay the question of peace or war before Magnus, the Moon King, and his lords. The Seven had won Horta over finally by offering him all the Earth secrets of the red rays that had made Earth-Moon travel possible. They had even set up a ray reservoir in Horta's great cavern, and had shown him how the harnessed rays could provide power for ships and explosive for sky-torpedoes. Yet Horta had never succeeded in building any but tiny ships that could barely circle the Moon, and he had denied any success with the torpedoes. Only on the ray-type and the ray-phone, essential to Earth-Moon intercourse, had he followed instructions with real results.

"Blue rays, then?" muttered Ross, staring at Moore. He turned as Jorgens appeared hesitantly. "Well?"

"Garbled message by ray-phone from our Earth station, sir. From Censor Trowbridge, apparently." Jorgens handed over a sheet of paper. "We put it down as we heard it."

Ross and Moore bent over it eagerly. "... trouble ... Moon ... Four ... Magnus killed...." It ended with "... bridge."

Ross wheeled on Jorgens. "Magnus—killed? Is that what you heard?"

Jorgens shook his head. "That's what it sounded like," he insisted. He flicked a hand at the ray-phone. "And that's all we got. She went dead on us. But," he added hopefully, "the ray-type seems to be coming to life."

"Good! Work on it, Jorgens. And try for the Peak One Moon station, or Peak Four." Ross watched Jorgens join the little group of signalmen toiling over the ray-type machine, and shook his head. "Did you get that, Harry? Magnus killed."

Moore blinked inquiringly. "Do we go on?"

"Go on?" Ross hesitated. He read the mangled dispatch, then squared his shoulders. "Nothing here about turning back. So on we go. Heaven knows what we'll find."

"Magnus dead." Moore shook his head. "Who takes over?"

"On the Moon? I happen to know, because it came up at the conference five years ago. Queen Boada and the two chief lords form a Council of Three. That'll be Boada, Horta and Artana, Lord of the Peaks. You remember him?"

"Sure." Moore wagged his jaws, chewing reminiscently. "Nice kid."

"Well, he was sixteen then. He'll be twenty-one, grown up. And say! Remember the Princess? Illeria. She was fourteen, she'll be nineteen now. Sweet kid."

"Skinny," grunted Moore.

"Yes," Ross agreed absently. "Well, we'll get a welcome from Boada and Artana. Maybe Horta will kick up a fuss, but he's the minority."

The ray-type machine came to life with a faint rattle. Jorgens watched it critically, then stared as the words ran out on the page. He waited for the sentence to finish, then snatched the sheet from the machine and held it out in trembling fingers to Ross.

The message was brief. Ross read it, shoved it at Moore, and grasped the orders tube. "Gun crews!" he sang out. "Load fore and after torpedo tubes and stand by!" He waited for the "Aye, sir!" to sound from both gun stations, then turned back to Moore.

The navigator was standing with jaw agape. He repeated the message word for word as if in a hypnotic spell. "Nagasaki destroyed. Purple Death."

Ross shook his arm. "Harry, snap out of it! We've got to fight!"

"Fight what?" asked Moore dazedly.

"I don't know," rapped Ross savagely. "But at a guess, I'd say the Purple Death, whatever that may be!"

II

The assistant navigator looked back from his post by the helmsman. "Coming in to Peak One, sir," he called.

"What's our speed?" asked Ross.

"Two thousand, sir."

"Cut her down to a thousand," commanded Ross. "Any signals from the Peak?"

The navigator shook his head nervously. "None yet, sir. Shall I cut speed if they don't signal?"

"Yes," Ross decided. "Slow up as you see fit, and hover at fifty miles if they show no signal." He gestured to his chief navigator. "Come on, Harry, let's inspect ship."

The two passed from the control room to the gleaming engines. Here the silent engine crew hearkened to the pulse of the powerful rocket engine, and kept steady eyes on the gauges that showed the compressed ray fuel was feeding steadily into the discharger. Out of the engine room they passed to the after gun station. Ross tapped one of the six-inch torpedoes, and slapped one of the slim three-inch cylinders in the number two torpedo rack. "We may need them all soon," he told the station chief.

The gunnery chief's eyes widened. "We'll be ready, sir. Can you—is there anything I can tell the men about—Number Eight?"

Ross shook his head. "She's gone," he said briefly. "Might have been an accidental explosion—but I don't think so. We're landing soon. Just be ready, that's all."

He swung away to the forward gun station, saw that all hands were alert, and led the way back to the control room. Jorgens was pulling a sheet from the ray-type. He handed it over quickly.

It was from the Moon. "Warning to Earth Fleet!" it began. "Peak One wrecked. Come in on Peak Four." And it was signed "Artana."

Ross strode forward, his blue eyes blazing. "That's all, Jorgens?"

"No, sir. More coming now." He waited until the flying keys had rattled out two more lines, then ripped the sheet off. This message told more.

"Peak One wrecked by rebels who assassinated King Magnus. Signal systems at Peaks One, Two and Three destroyed. Greetings to Commander Ross. Artana."

"Rebels!" exclaimed Ross.

"Horta!" murmured Moore.

The chief signalman caught the name. "That louse!" he exclaimed in disgust. "Pretended we couldn't teach him anything, the time we set up his systems for him. He's raising hell on the Moon, Commander?"

Ross frowned. "That's just a guess, Jorgens," he reproved the signalman. "We only know this much for sure." He tapped the two sheets.

"Huh! Ten to one that blue-nosed devil's in it," grumbled Jorgens, turning back to the ray-type. "Want to answer, Chief?"

"Yes." Ross thought rapidly. He spoke in a low tone to Moore. "This might be a trap."

Moore blinked. "You mean, Artana sent this to decoy us in to Four and smash us?"

"Not Artana," corrected Ross. "Horta."

"Gosh, yes!" Moore fumbled his glasses off. "I hadn't thought of that! No reason why Horta couldn't send a message in Artana's name!"

"It's a possibility," Ross grinned sourly. He turned to Jorgens. "Send this: 'Greetings to Artana, Lord of the Peaks, from Ross. Coming in to Peak Four.' Repeat it, too, in case they aren't getting it any too clear." He wheeled to the helmsman, noted the speed was cut down now to six hundred miles, and nodded approval. "Change course for Peak Four."

Moore laid an urgent hand on his chief's arm as the helmsman obeyed. "Say," Bruce, this is risky!"

"Risky!" Ross laughed shortly. "Of course it's risky."

"Wouldn't it be better to stand off and wait for more news?"

Ross shook his head. His eyes blazed. "Harry, there's a lot of hell breaking out on the Earth and on the Moon, too. We're in the middle. We can't be in both places, but we can find out—I hope—what's going on up here. And if we do, maybe we can put a heavy foot on what's happening to the Earth. Do you remember what Trowbridge's message said?"

Moore's ordinarily placid features tightened. "The Purple Death," he whispered. "You're the boss, Bruce. All I want is to get in on whatever happens!"

The Earth Fleet slid slowly down to the craters. The pale surface of the Moon gleamed dully, phosphorescent, lambent where the rays of the sun struck crater tops. Off to the left the High Peak, Peak Number One to the Earth visitors, loomed dark and sinister.

But Peak Four showed all its lights, bright and steady. Ross ordered the six following ships to stand off and await orders, or act on their own judgment if the flagship came to harm. Then he took his place beside the helmsman. "Take her down slow," he ordered.

The rocket ship glided straight and sure for the brightest light. Slowly the pin-point of white fire became a circle, then an oval. Then it broke up into hundreds of lights surrounding a platform. The helmsman muttered an order, and the rocket ship, answering the urge of her flippers, dived briefly and straightened out into a glide. From the control windows the shape of the platform took form, and dim little figures could be seen scurrying on its edges.

Moore fidgeted uneasily. "We'll be duck soup for them if it's Horta," he muttered.

Ross chuckled. "Where's your sporting blood?" he jibed. "Bet you even money it's Artana."

"That's an easy bet for you," retorted Moore. "You won't live long enough to pay off if it's Horta."

The crew of the ship seemed to share his fears. Every man hunched tense at his station. The ship glided lower, to three hundred feet. Two hundred. She lost way almost entirely, and grounded with scarcely a jar.

"Nice set-down," Ross complimented the helmsman.

Instantly the crew sighed in unison. Tension was broken. They peered through the windows.

"Back to your stations!" rapped Ross. He glanced through the control port and immediately saw a group advancing toward the ship. For an instant he held his breath. Then he whooped. "It's Artana!"

The crew cheered, briefly, knowing nothing of the importance of that single identification. Two artisans stood by the gangway, waiting.

"Secure your helmets, men!" shouted Ross. He adjusted his own headgear, made sure that the thin tubes from his breastplate were feeding their tiny jets of oxygen to his nostrils, and signaled to the artisans. They threw the door wide, and Ross stepped forth to meet Artana.

The young Lord of the Peaks came forward with a glad cry. "Ross!" he exclaimed, and grasped the Earth-man's hand warmly.

"Artana!" cried Ross. He eyed the Moon Lord from head to foot, and grinned. "You've grown, Lord of the Peaks!"

The boy he remembered was indeed now a man. Matching the six-foot Ross in height, he stood straight and slender, carrying easily the weight of the ray-rifle slung on his shoulder, and the poison-pistol at his belt. He smiled briefly at the Earth-man's sally, then sobered at once.

"You come at a critical time," he murmured, pitching his voice so that his half-dozen followers could not hear. "The Moon People are divided by revolt, and the fate of the Kingdom is not easy to predict." He caught sight of Moore. "Ah, my friend Harrell Moore!" His hand went out in a warm clasp.

"Hi, Artana," returned the navigator awkwardly. "You're looking great. What's the trouble? I'll guess it's Horta."

"Softly!" Uneasily the Lord of the Peaks glanced about him. "Let us go to the Peak Chamber, where we may speak at ease." He led the way from the platform, halting only to allow Ross to relay an order for his six ships to land. Through a winding subterranean corridor they hastened to the council room of the Peak, which marked the administrative center of one of Artana's provinces. Once inside the great room, Artana led them to low divans of stone, covered and made comfortable with soft cellulose-like stuff that rustled as they moved. He gave them the news bluntly, without preamble.

"Horta has seized power in two-thirds of the Kingdom," he cried, his voice breaking with emotion. "King Magnus was killed, perhaps not by Horta's orders—but who else would have plotted it? The assassination seemed to be the signal for an uprising—and Horta issued a proclamation, as one of the three regents, declaring that he would act to preserve order in the Caverns and the land beyond where the Crater folk live. Three of the Peaks were overrun, and the signal systems were all destroyed. Here at Peak Four, my soldiers were ready, and all the rebels were slain."

"Queen Boada—and the Princess Illeria?" asked Ross.

"They are safe." Artana twisted on his couch in his distress. "They were at Peak Five when the attacks were made, and are coming here, escorted by a strong body of my troops. I expect them soon. But you, my friends? How can I receive you, when my people are embroiled in civil war—for that is what it is?"

Ross waved his hand deprecatingly. "Don't worry about us, Artana. Of course, we can't take sides here. We can help to preserve the Regency, since the Truce demands it. But there's one thing I'd like to ask."

"Of course, my friend."

"Have you heard of trouble on the Earth?"

Artana looked up quickly. "We have had no word."

"Or—well, trouble in the sky?"

Artana shook his head, puzzled.

Ross answered his unspoken question. "One of our ships was destroyed on our flight from the Earth. And I don't think it was an accident."

"A rocket ship?" Artana sat up. Then his eyes flashed. "Horta?" he murmured, as if asking himself a question.

Moore leaned forward. "Has Horta been up to anything in the ray business?" he asked eagerly.

Artana shook his head slowly. "Lord Horta and his savants have made progress in employing the R-ray, drawn from the red stars, as you taught him." He knit his brows. "I have heard of nothing else—but wait. He and his most learned men have worked secretly for many moons, I know not to what purpose. You think—"

"We think," cut in Ross grimly, "that it's possible that Lord Horta may be cooking up something new in the ray field."

Artana's face darkened. "If that is true," he murmured, "we may have the explanation of the disappearance of two of my brigades. I sent them out in force to scout Horta's territory. No word has come from them." His hand clenched. "A war of rays—here on the Moon!"

Ross and Moore exchanged uncomfortable glances. They had fought in the terrible war on the Earth when nations battled with the new red ray, and whole fleets of the ancient steel warships were sunk by the first of the ray-torpedoes, before the Council of Seven was formed to rule all Earthly affairs. And they had served in that first Moon-flight, and had slain with rays the first Moon armies who had resisted the intrusion of the Earth-fleet. Was history to repeat itself—in reverse, with Horta's Moon machines raking the Earth with death? Perhaps that strange Purple Death of the Trowbridge message?

Ross made his resolve. "If your armies can't find out what Horta's doing, Artana, perhaps my fleet can."

"Your fleet?" Artana looked up, a flicker of hope in his somber eyes. "You mean that you would fly over the Caverns?"

Ross nodded. "And study the work he has done. Photograph it, and report to you and the Queen. If you then wish us to try to destroy it, I'll take the responsibility. I feel that the Council of Seven would approve."

Artana stood up, his eyes alight. "Ah, Ross! If you succeed, and bring peace to the Moon people, your planet and mine will do you homage!"

Ross flushed sheepishly. "Well, maybe. For my part I'd rather be overlooked. You know, there's an old, old saying where I come from, 'A hero today, a bum tomorrow.'"

"A 'bum'?" echoed Artana, puzzled.

"A-a sort of—" Ross remembered in time that there were no beggars on the Moon. Nor panhandlers, nor paupers, nor hobos. "Oh, never mind. We'll take off in the first hour of light, and see what we can see."

"In the meantime," Artana hastened to say, "you must sleep." He ushered them into a circular chamber, the elevator that would take them to the spacious under-world of the Moon. Closing the door, he pressed a button. The resultant motion was almost imperceptible, but Ross and Moore knew they were being hurtled toward the Moon's core at hundreds of miles an hour. Almost instantly the chamber stopped, the shock of cessation being oddly cushioned. Artana opened the door, and the three stepped into the great rotunda whence radiated the life and activity of the Province of Peak Four. Moon people hurried to and fro, only a few stopped to stare at the Earth-men. Bakers were hawking the curious brick-shaped loafs of bread, and the fruits that had grown from the seeds from the Earth were stacked on stands. Drapers stood by their gossamer-like fabrics. Soldiers hurried to and fro in squads, and their presence explained to Ross and Moore the inhabitants' disinterest in the Earth-men.

The spacious chamber to which Artana led them was guarded by two tall sentries, and tastefully furnished. The Lord of the Peaks cast a last glance about, said, "I shall call you at the first light," and vanished.

Moore sank gratefully down upon a high-piled bed. "Well, if this is to be my last night's sleep, I'm going to do well with it."

"You're always worrying," chaffed Ross. But he lay, awake, mind racing, long after Moore's even breathing denoted that the chubby navigator's fears had succumbed to his fatigue.

III

Artana awakened them as he had promised. His first words were of the widowed Queen. "Boada is here," he told Ross. "She has slept, and will greet you after you have eaten."

They breakfasted in the chamber, on food that Artana had commandeered from the rocket ship, with some of the pale, delicious Moon pears beside the familiar Earth fare. Artana talked fast as the two Earth-men ate.

"Two of the Cavern men came in with the Queen." As the two flyers looked up in plain surprise, he smiled. "Yes, they were Horta's men. But they say they do not wish to serve him longer. They say he plans to rule the Moon Kingdom alone, and will make war with the Earth."

The two leaned forward, food forgotten. "Did they say," asked Ross, "how Horta plans to make war? With what weapons?"

Artana shook his head sadly. "They deny all knowledge of such things. They are star savants, and they say all Horta's war secrets are known only to his war chiefs."

The flyers' disappointment impelled Artana to go on. "They do say that Horta and most of his forces are gathered in the Great Cavern, where all his secrets are kept. And that, too, is where he has set up his ray machines."

Ross narrowed his eyes. "The Great Cavern, eh? Well, that's what we'll have a shot at."

"You would have me accompany you?" Artana asked eagerly.

"Ah, no, Artana. You are needed here. What if Horta were to make a sudden attack? You must give us a guide, though, to show us the Great Cavern. And I will leave my chief signalman, Jorgens, so that we may keep in touch with you."

Artana assented, somewhat cast down. Truly, the Great Cavern held a secret, and the Lord of the Peaks was as eager as any to learn it. But he regained his cheerfulness as they sought out the Queen.

She was in the great chamber where Artana had first received the Earth-men. Erect and haughty, she sat on the central divan, regarding them with brooding eyes as they entered. So much Ross saw before his glance went to the slim figure beside her. He caught his breath.

A dream! A goddess! This girl—ah, yes, the Princess Illeria. But a woman now! Not the scrawny girl of five years ago. Ross tore his eyes from her with a jerk. Artana was presenting him to the Queen Widow.

"—Commander Ross, leader of the Earth-fleet, was a visitor at court five years ago," Artana reminded the Queen.

She extended her hand, surveying him with a softening of her austere expression. As he bent over it she said in a harsh voice that was obviously held steady with an effort, "Commander Ross, you come at an unhappy time."

Ross murmured condolences, then plunged into the subject that was filling him with impatience. "I seek permission from you, Queen, and from the Lord Artana to fly over the Caverns and report on conditions there."

Queen Boada darted a sharp glance at Artana, then averted her head. "I see no occasion for such a flight," she said curtly.

Artana stepped forward. "A rebellion, O Queen? Surely that is occasion enough?"

She met his eyes, frowning. "But these are not our people."

"Yet," argued Artana, "the Earth people are at peace with us."

Ross saw the Princess regarding her mother curiously. Moore, too, was staring in frank astonishment at the Queen. As she sensed their intent regard she relaxed her rigid pose. "Oh, very well. But there shall be no fighting?"

"None, O Queen," Ross hastened to say.

Artana nodded with satisfaction. "There remains, then, the finding of a guide for the fleet. I could send Calisto—"

The Princess spoke for the first time. "Calisto has not the gift of the Earth-tongue. Who guides the Commander Ross must speak the tongue he knows best."

"That's true," muttered Artana, taken aback. "Who, then—"

The Princess was looking at Ross. Almost hostilely, he thought confusedly. Had she resented his long open stare? She was such a picture, clad in only a single filmy garment, caught at the waist with a gold twisted belt and cut tunic-like at the knee. Bare-armed, with softly swelling contours and a skin like peach down, she was an entrancing sight.

His confused thoughts were set at rest. The Princess had a plan. "I shall go with the Commander Ross," she said.

The Queen turned sharply. Artana scowled. "No, no!" he cried sharply. "If there should be fighting—"

"Fighting?" echoed Boada in a whip-like tone.

"No, no, not fighting," Artana hastened to correct himself. "But danger, perhaps."

Boada's brooding gaze came to rest inquiringly on Ross.

"There can be no danger, I think," he assured her. And wondered why he did so. For if Horta was on the war path, surely the Earth ships would be his targets.

He felt his heart beat faster as he considered the possibility of this amazing girl standing beside him in the control room of his flagship, then a moment of depression as he reflected that the queen would refuse her consent. But to his surprise Boada, after one dark look at the Lord of the Peaks, nodded.

They left at once. There was a moment of delay when Illeria, given an oxygen helmet, demurred at the idea of wearing it until she was convinced that it would save her life if the shell of the rocket ship were pierced in the upper air. She wore it with ease, the straps fitting snugly over the flowing golden locks and the oxygen tubes crossing her face to add to the piquant enigmatic look she wore.

The flagship took off with a rush, the six following ships keeping their distance. Once in the air, they formed the echelon. Then Ross turned to the princess, and led her to the telescopes trained through the floor of the ship.

She studied the crater surfaces wonderingly, like a child with a strange toy. Then she remembered her duty. "Sail there," she directed, pointing.

Amusedly, Ross gave the order. Privately Artana had given him a full description of the Great Cavern, so that once he had sighted it he could map his own course. But the girl had guided him truly. In a few minutes the yawning chasm lay on their bow.

He called Moore. "All the cameras set?"

"All set," grunted Moore, squinting through a glass. "Going to skirt the cavern?"

Ross nodded. "No use tipping Horta off at the outset. We may get a good look without his knowing we're here."

As the last word left his lips a cry from the port lookout froze the three in their places. They turned, fearfully. The lookout's face was working. As they watched, tears began to stream down his face. He tried to speak, but he could only point.

Ross sprang to the window. The sky was clear, save for the following ships. Number Two, and Four, and Five. Six? Where was Six? And Seven? He whirled on the lookout.

The man gulped, drew a deep breath, and said huskily, "There was a flash, sir, and—and then—nothing! Nothing, where Number Seven was flying! And then Number Six—went the same way!"

Ross and Moore stared frantically at one another. Then Ross sprang to the signal post. "Jorgens! Where's Jorgens?"

A white-faced signalman spoke up. "He's back at Peak Four, sir."

"Oh, yes." Ross in his agitation had forgotten. "Well, signal Ships Two, Three, Four and Five to sheer off the Cavern and return to Peak Four!"

The man sprang to obey. Ross turned to order the course changed. But the crashing din that followed silenced him. His body hurtled against the stanchion, and suddenly he found his arms about the Princess Illeria.

Her body was soft to his touch, her silky hair caressed his cheek, her breath sweet on his face. But he pushed her aside, and cried out to the helmsman, "How does she fly?"

The helmsman, craning his neck as he curled an arm about the wheel, shouted back, "On even keel, sir, but she won't steer!"

Ross pushed the Princess unceremoniously from him and stood erect. He rushed to the window and saw with relief that the ship was circling away from the Crater. Gauges showed that the ship flew steady except for that odd circling. An artisan, bursting into the control room from the after gun station, explained the mystery.

"One rudder flange haywire, sir!"

"So that's it!" Ross spoke calmly. "Shot away?"

The man's face worked. "Burned away, sir!"

"Burned—" Ross thought fast. He nodded to the artisan, who departed with a scared look about.

Moore had heard the report. He whistled. "Burned away, huh? Sounds like a B-ray."

"B-ray? What's that?" snapped Ross.

"B for blue," explained Moore affably. "Horta's draining the blue stars, or I'm no Harvard man."

Ross eyed the navigator narrowly. "You really think that?"

"What else?" countered Moore calmly. "Horta was a washout on the R-ray—and besides, our red ray doesn't burn like that. I think Horta's got something."

Ross turned to the helmsman, then studied the chart that Artana had provided. "We can circle just like this, and make Peak Four if we can cut that drag a bit. Try reducing the speed."

It worked. At reduced speed the ship flew more truly, with less pressure on the rudder. Ross sighed in relief. "Keep her there." He spied the Princess leaning against the stanchion, and walked over. "Quite a scare, wasn't it?"

She regarded him steadily. "You do not like me?"

He gaped at her. "Why do you say that?"

"You pushed me away from you."

"Oh, that!" Ross was nettled. "A man must fight his ship, Princess."

"Yes." She nodded agreement. "But I was afraid. I thought we were doomed. And I wished you to be with me. It is not given to every woman to die with the man of her choice. And you are the man I wish for."

Ross stared open-mouthed. "Say-ay!" he asked cautiously. "You didn't get a knock on the head, did you?"

She shook her head unsmilingly. "The Earth-girls, they do not speak so to men?"

"I'll say they don't," Ross assured her feelingly.

"Oh!" said the Princess Illeria in a small voice.

Ross didn't know what to say then. "Well," he exclaimed, "we'll soon be back at Peak Four."

He was right. But grim news awaited them at the peak.

IV

Artana met them, his face a thundercloud. He handed Ross a ray-typed message. "This came just before you landed," he said tensely.

Before Ross could read the message, the name signed to it caught his eye. Horta! The Lord of the Caverns was coming out of his silence! And with what a greeting! "Know, O Queen," read Horta's message, "that I have destroyed three of the Earth-ships, as I shall destroy all who fly against the destiny of the Moon Kingdom. Know, too, that I have destroyed a second Earth city, the place called Los Angeles, as a warning to the Earth people that their destiny is not ours."

Ross read it with a sinking heart. Los Angeles! A city of two million people, destroyed! Then it was Horta who had wiped out Nagasaki!

Moore pounced on that thought. "Nagasaki, then Los Angeles!" he muttered.

Ross turned to Artana. "Any other news?"

Artana shook his head. "No. But I have a plan. You know that when the rains come we store them in the great reservoirs, so that our under-world may not be flooded. Then why not loose the waters in the reservoirs, and flood the caverns?"

Ross stared in admiration. But he slowly shook his head. "You'd have to kill half your people, Artana, just to dispose of Horta."

"But," argued Artana desperately, "Horta will destroy half our people himself, to seize the Kingdom. And he will destroy the Earth folk, too!"

Moore spoke up. "The reservoirs are full?"

"No," admitted Artana. "The rains have not been heavy. The reservoirs are but half full." He sighed. "Horta might escape the flood."

"That's no good, then," Ross said emphatically. "Tell you what, Moore and I will go and scout the Cavern on foot. We may be able to get near enough to the ray works to smash 'em."

"You would die," Artana said somberly. "Horta guards his Cavern well."

Ross nodded. "Maybe. But there's no other chance. Horta can knock us down out of the air, and he's knocking Earth cities to dust. He must be stopped. If we die, you can hold out on the Peaks, and flood him out when the rains come."

"That's right, Artana," Moore agreed. "But let me go, Chief. I'll take a couple of good men. You stay here."

"No dice, Harry," Ross assured him firmly. "I'm the head man and it's my job. I'd like to have you along, though."

"Sure," said Moore mildly.

Artana regarded them with admiration. "You are brave men! But what can I do?"

"Just sit tight, Artana, and wait for the rain to fall," grinned Moore. "And when it comes, avenge us."

"That will I!" swore Artana.

They set out in the dark, Moore and Ross and the guide whom Artana had indicated with a gesture. They had covered only half a mile when Ross turned sharply, suspiciously, to the guide. "Sure you speak the Earth tongue?" he demanded. "If you do, why can't you say something?"

The guide threw back the cowl-like head covering and Ross caught his breath. "Illeria! What are you doing on this tour?"

"I go to die with you, my lord," said the princess simply.

"My lord!" squawked Moore. "Excuse me!" He walked forward hurriedly.

Ross, his face burning in the gloom, took Illeria's arm roughly. "This is no job for you, Princess! There will be danger!"

"Even death," agreed the slim princess equably. "No matter. And the Lord Artana is agreed that I go."

"Artana agreed?" Ross was taken aback. He looked ahead to where Moore waited, looked back over the way they had come, then shrugged. "Oh, well! Here we go!"

Happily Illeria caught his arm, and they strode forward. Moore chuckled in the dark. "Everything settled?"

"Yes, dammit," grated Ross. "Did you ever see such a mess?"

Moore's reply was sober. "We couldn't have a better guide," he pointed out. "And we know the princess is loyal. How could we be sure of some other guide? A jigger who might sell us out to the first Horta sentry?"

Ross grunted agreement, and they trudged on. They saw no one, heard no one, until the first of the craters lay behind, and the Moon terrain sloped down and down into the caverns. They came upon the first two sentries suddenly. Both swung their ray-guns up, but Moore was quicker. His gas-pistol spat twice, and the sentries crumpled.

"Are they dead?" asked the princess, amazed.

"Dead to the world—er, I should say, dead to the Moon," Ross assured her. "They'll stay that way twelve hours, which ought to be long enough for us."

Moore chuckled. "Before then we'll be on top of the world—I mean on top of the Moon—or dead heroes."

The way was easy, a steady down slope, for a while. Then the rock formations began. They slipped and crawled. The princess suffered a cut on her knee, but shrugged at the suggestion of a bandage. The second set of sentries were easily overpowered. They lolled at ease against a ridge, and Ross shot twice to gas them to sleep. Here the light was better, and Ross paused to look them over. They were darker than the Peak men, with less color, and their veins stood out against their blue-white skin. They bore the ray-rifle of all the Moon soldiers, and another curious weapon besides, a jagged-edged sword with a hooked point.

"It's the old Moon sword," said Illeria. "Horta worships the old customs, and swears by the beliefs of the astrologers. It's the astrologers who direct his actions, my mother had said."

"It's a dirty weapon," shuddered Moore. "I'll take a ray-gun any time."

He came within an ace of regretting his choice a moment later, when a whole squad of soldiers rounded an outcrop of rock. Ross whispered a warning, and shot fast. Moore went into action then, but not before one of the Horta men had fired. The ray blasted past them and sheared off a half-ton of rock behind them.

"Whew, that was close," gasped Moore as the last of the soldiers fell.

"How about ray-guns now?" gibed Ross. "Do you know, I think we're in luck. This party is evidently supposed to relieve the sentries we met—so there'll be no alarm over their condition."

"You're right!" exclaimed Moore. "Now all we have to do is to get to that ray machine!"

They stood within sight of it when the heavy hand of Horta fell.

In the shadows of the cavern they had crept from arsenal to foundry, until they had inspected from far or near every establishment in this dim and fearsome chasm. And finally they saw it, a great cylinder nestling deep in the ground and looming high in the cavern, supported by guy beams of gleaming metal.

"A ray-gun!" cried Moore. His incautious exclamation was their undoing. A half-clad foundry worker, looking like a gnome in his eye-shade helmet and drooping gauntlets, gaped at them. Ross shot a split second too late to stop the shout of alarm. The foundryman dropped, but a dozen soldiers came on the run. Moore and Ross fired and fired again, but they went down in a charge of scores of Horta soldiers. The flat of a sword struck Ross a stunning blow on the side of his head.

He came to his senses to find himself in a strange room, bound hand and foot and prone on a stone floor. Beside him was Moore.

"Where are we?" muttered Ross.

"In Horta's headquarters," whispered Moore. "Here's Horta."

Ross twisted his head. He blinked. For Horta was an eyeful.

The Lord of the Caverns was a giant. Fully seven feet tall, he must have weighed four hundred pounds. But he bore his great bulk with ease and a certain dignity. He strode over to the two prisoners, looked them over with curiosity but without visible rancor, and spoke sharply to a guard in the Moon tongue. The guard hastened to free the two flyers.

They exchanged glances of surprise. "You don't suppose he's a pal in disguise?" asked Moore blandly. He looked up with a start when he heard a rumbling chuckle.

Horta was amused. "No, Earth-man. You are prisoners. But I have no need to bind you, for you cannot escape. Yet you need not fear death, for if you will stay and serve me you shall have life and all the blessings that will be showered upon a new Kingdom."

"New Kingdom?" Moore blinked. "It's a Regency, isn't it?"

Horta's great laugh boomed out. "Nay! I am the King! And for my queen—well, you have delivered her to me!"

Ross sat up and stared. "You mean—Illeria?"

Horta chuckled as he nodded.

"Illeria!" Ross stifled a curse. His mind raced. The girl was a prisoner, too. He spoke aloud, easily. "Well, I guess we can give Your Royal Highness a hand."

"Hey, Bruce!" Moore expostulated. "You don't mean—"

"Why not?" drawled Ross. Turning to face Moore, he winked. "We know a lot that will pay our way with the new Kingdom."

Moore blinked. "Of course!" he assented hastily. "Sure!"

Horta stared suspiciously at the two flyers. "Make sure, then, that you have no secret longings to return to Earth," he warned heavily. "For henceforth there shall be no intercourse between Moon and Earth. The truce is ended."

Ross ventured a question. "What'll you do with the men of the Peaks?"

Horta smiled grimly. "They will submit, or die." He gestured imperiously, and the guards pushed the flyers forward as Horta strode from the room.

As they trailed behind, Moore whispered, "He doesn't look like a killer."

"Probably a fanatic," Ross muttered.

"What's the play?"

"Watch our chance, and wreck the ray machine."

"And us with it," grumbled Moore.

"Most likely," Ross agreed.

They entered a softly lit room, in the wake of Horta. As their eyes became accustomed to the dim light they gasped. There was Illeria. But beside her was the queen—Boada!

She swept them with a glance in which contempt was mingled with a kind of pity. "You did not expect to see me here," she said harshly. "But I serve the destiny of the Moon. The wise men have shown me that the Moon was never destined to serve the Earth, but must stand with the Blue Stars when the Universe is rent asunder. And now the Moon is ready to defend itself, thanks to the new King Horta!"

In the silence that followed Ross heard the girl gasp. The queen spoke softly. "And you, my daughter, shall be the new queen, wife of the almighty Horta the Liberator."

"Not," Ross muttered between his teeth, "if I can help it."

"Me, too," whispered Moore.

The girl said nothing. But her eyes sought Ross with piteous entreaty.

Horta broke the silence. "The nuptials shall be solemnized in tomorrow's full light. You, Earth-men, shall remain under guard until you have given earnest proof of your fealty."

The guards punched the two as Horta rapped an order in the Moon tongue, and they allowed themselves to be led away. Through a dim corridor they passed, and into a stone cell, with oddly fashioned stone bars and a door that slid on a metal base, locking them into their tomb.

Ross circled the cell, then shook his head. "We couldn't get out of this without a ray machine," he muttered.

Moore sat down against a wall. "Guess not. Say, Bruce, did you hear the old girl?"

"The Universe is to be rent asunder," grunted Ross. "Where does that leave us?"

"Behind the eight ball, as I believe they used to say back in the twentieth century," grinned Moore. "That is, that's where we would be if the Universe really were to be rent asunder."

"Oh!" grunted Ross in heavy sarcasm. "So it isn't going to happen?"

"Gosh, no," chuckled Moore. "It's the silliest kind of astrological fake, discredited two centuries ago. Where Horta picked it up I don't know. Probably he got some power from the blue stars by accident, and his faker astrologists strung him along on the big bust-up idea."

"Nice clean fun," muttered Ross. "Well, we missed. Horta's still got his ray machine. He's also got the princess—and the queen for an ally."

"He's also," amended Moore dryly, "got us."

"And how," grunted Ross. "How long do you suppose we'll last if we don't—"

He stopped abruptly. A faint noise came to his ears. "Hear that?" he asked, puzzled.

Moore cocked his head to one side. "Running water," he remarked. "They haven't got a river down—"

A scream, faint and far away, took his breath away. Another sounded, and then a chorus, dimmed by space and the stone walls. Suddenly Ross and Moore whirled to face one another.

"Artana!" cried Ross.

"He's opened the reservoirs!" gasped Moore.

They leaped to their feet. Ross tried the door, savagely. Moore broke the skin of his hands on the stout stone bars of the window. In a moment, water was swirling at their feet.

Moore stared down at it gloomily. "I was two days on a raft in the middle of the Atlantic," he sighed, "and I didn't drown."

The water rose to their knees.

V

Ross tugged at the door. "You aren't drowned yet. How did this door open?"

"From the outside," grumbled Moore, tugging with his chief. "It rolled—ha! It's opening! We've got it!"

The door was sliding open. A rush of water swept them half off balance, and they splashed into the flood when the Princess Illeria catapulted into them.

"Princess!" yelled Moore. "Good girl!"

Ross gripped her arm. "What's going on?"

"Panic," she panted, clinging to him. "Horta and his steadiest men are at the ray machine, fighting to keep the water out of the ray reservoir. The Queen went with him. I'm—afraid—"

"Cheer up," Ross consoled her. "And let's get out of this." He led the way out of the cell. Water was waist deep in the corridor. Ross pointed up an incline, where the swirling waters ran thinly. "Looks good," he suggested. He whirled then on Illeria. "Where do you suppose we could get some guns?"

"What good would they do?" growled Moore.

"There's that ray machine," Ross reminded him.

"Oh! Yes. But—" Moore shot a glance at the Princess. "Don't forget—the Queen—"

Ross scowled. "I know."

Illeria touched his arm. "If the Queen must die, that the Moon people and the Earth folk may be saved, let it be so," she urged simply.

The two men bit their lips.

"Come!" urged the girl. "There is a guardroom above. There must be weapons."

"I could use one of those antique hook-'em swords on old Horta," growled Moore.

They burst into the guardroom prepared for sudden and violent action. But the great chamber was empty of Moon men. On the walls hung ray rifles. Ross and Moore each snatched one.

"Now where?" asked Moore.

Ross surveyed the room. Windowed on all sides, it had only two doors, the one they had entered and another opposite. "We'll try that," Ross decided. "What we've got to find now is a spot that commands the square where the ray machine is bedded."

The sloping corridor led them to such a spot. On a balcony they stood and for a moment were content to watch Horta's artisans toiling with sandbags and debris to make barricades against the flood.

"They'll do it, too," Moore said aloud, voicing his chief's thought.

"Artana's trick was probably just to help us out," Ross judged. "He hadn't enough water to flood 'em out."

Moore fidgeted. "Let's do something, Bruce! There's that ray reservoir. Think these pop-guns will punch a hole in it?"

Ross raised his rifle, and lowered it as suddenly. For into sight, beside the giant Horta, walked Queen Boada. Moore exclaimed under his breath, fingering his rifle.

It was the Princess Illeria who, snatching the rifle from Moore's hands, leveled it swiftly and fired. As Ross sought to snatch it from her she faced him defiantly. "Let destiny rule us!" she exclaimed. "My mother is an unhappy woman who stands in the way of peace. Let me fire again!"

Her demand left Ross irresolute. As he held her hand, Moore cried out. "They spotted that shot, Bruce! They're looking for us!"

It was true. Horta stood, legs spread, his fierce glance sweeping the open space. Workers had begun to drop sandbags and pick up guns. Ross loosed his hold.

"Let's fire together, then," he said heavily. "The double shot may pierce that thick metal. Aim at the muddy mark, Illeria! Ready—fire!"

The two rifles spat together. Moore yelled, "You've done it! Duck—fast!"

They could not take cover fast enough. Ross had one glimpse of a tremendous sheet of flame licking out of the hole they had blasted, saw its counterpart high in the sky at the mouth of the ray cylinder, heard a great roar, and seemed to know nothing else.

He regained consciousness on the platform of Peak Four, where his flagship, now repaired, rested airily. Artana, Moore and Illeria bent over him solicitously.

"What happened?" he asked, fretfully.

Artana spoke soberly. "The Queen is dead." He turned to Illeria, dropped to one knee, and bowed his head. "Long live the Queen!"

Ross glanced at Moore. The navigator winked. "Order is restored, Chief," he explained. "That blow-up finished Horta and all his works. And Earth is on the phone. All serene there, since the Los Angeles disaster. You are ordered to return and report."

Illeria dropped to her knees beside Ross. "You will not go? You will stay—and my people shall make you king!"

Ross looked long into her eyes, and the Earth seemed far away and an unreal world. But he slowly shook his head as he rose and gently lifted her to her feet. "I must go, Illeria," he said. "But—perhaps I shall return. Good-bye, Artana, you will restore peace to the Moon."

The Lord of the Peaks bowed his head, "That I will, farewell, Ross!"

With one last glance at the white-faced princess, Ross nodded shortly to Moore. They strode to their ship without a backward glance. At a curt order the helmsman took her off, and in seconds the two figures on Peak Four's platform had dwindled to specks.

"You can come back," Moore grunted.

"Think so?"

"Sure. When the Council hears what you've done they'll give you twenty years' leave. With pay."

Ross smiled. And the smile lingered as he turned to Jorgens to dictate a message for the Earth. The rocket ship droned on through space.