"Bong-g-g! Bong-g-g! Bong-g-g!—"

With a hollow booming sound reminiscent of old eighteenth-and nineteenth-century clock towers, the electronic time tone rang out from the Tower of Galileo, chiming the hour of nine. As the notes reverberated over the vast expanse of Space Academy, U.S.A., the lights in the windows of the cadet dormitories began to wink out and the slidewalks that crisscrossed the campus, connecting the various buildings, rumbled to a halt. When the last mournful note had rolled away to die in the distant hills, the school was dark and still. The only movement to be seen was the slow pacing of the cadet watch officers, patrolling their beats; the only sound, the measured clicking of their boots on the metal strips of the slidewalks.

On the north side of the quadrangle near the Tower, a young watch officer paused in front of one of the dormitories and scanned the darkened windows of the durasteel and crystal building. Satisfied that all was in order, he continued on his lonely way. A moment later a shadowy figure rose out of the bushes opposite the dormitory entrance and stepped forward quickly and cautiously. Pausing on the slidewalk to stare after the disappearing watch officer, the figure was illuminated by the dim light from the entrance hall. He was a young man wearing the royal-blue uniform of a Space Cadet. Tall and wiry, with square features topped by a shock of close-cropped blond hair, he stood poised on the balls of his feet, ready to move quickly should another watch officer appear.

After a quick glance at his wrist chronometer, the young cadet darted across the slidewalk toward the transparent crystal portal of the dormitory. Hesitating only long enough to make certain that the inner hallway was clear, he slid the portal open, ducked inside, and sprinted down the hall toward a large black panel on the wall near the foot of the slidestairs. On the panel, in five long columns, were the name plates of every cadet quartered in the dormitory and beside each plate were two words, IN and OUT, with a small tab that fitted over one of the words.

Out of the one hundred and fifty cadets in the dormitory, one hundred and forty-nine were marked IN. The slender, blond-haired cadet quickly made it unanimous, reaching up to the tab next to the name of Roger Manning and sliding it over to cover the word OUT. With a last final look around, he raced up the slidestairs, smiling in secret triumph.

In Room 512 on the fifth floor of the dormitory, Tom Corbett and Astro, the two other cadets who, with Roger Manning, made up the famed Polaris unit of the Space Cadet Corps, were deep in their studies. Though the lights-out order had been given over the dormitory loud-speaker system, the desk lamp burned brightly and there was a blanket thrown over the window. The boys of the Polaris unit weren't alone in their disobedience. All over the dormitory, lights were on and cadets were studying secretly. But they all felt fairly safe, for the cadet watch officers on each floor were anxious to study themselves and turned a blind eye. Even the Solar Guard officer of the day, in charge of the entire dormitory, was sympathetic to their efforts and made a great deal of unnecessary noise while on his evening rounds.

His brown curly hair falling over his forehead, Tom Corbett frowned in concentration as he kept the earphones of his study machine clamped tightly to his ears and listened to a recorded lecture on astrophysics as it unreeled from the spinning study spool. As command cadet of the Polaris unit, Tom was required to know more than merely his particular duty as pilot of a rocket ship. He had to be familiar with every phase of space travel, with a working knowledge of the duties of all his unit mates.

Astro, the power-deck officer of the unit, paced back and forth between the bunks like a huge, hulking bear, muttering to himself as he tried to memorize the table of reaction times for rocket motors. Though the huge Venusian cadet was a genius at all mechanical tasks, and able to work with tools the way a surgeon worked with instruments, he had great difficulty in learning the theories and scientific reasons for all the things he did instinctively. Suddenly Astro stopped, looked at his chronometer, then turned to Tom.

"Hey, Tom!" he called. "Where's that jerk, Manning?"

"Huh?" replied Tom, lifting one of the earphones from his ears. "What did you say, Astro?"

"Where's Manning?" reiterated Astro. "It's ten minutes after lights out."

"He was going to get those study spools for us, wasn't he?" mused Tom.

"He should've been back by now," grunted the Venusian. "The library closed an hour ago. Besides, he couldn't have gotten those spools. Every other cadet in the Academy is after them."

"Well, he's a pretty resourceful joker," sighed Tom, turning back to the study machine. "When he goes after something, he gets it by hook or crook."

"It's the crook part that bothers me," grumbled Astro. "Besides, if the O.D. catches him out of quarters, he'll be doing his studying while he's polishing up the mess hall."

Suddenly the door to the room burst open and slammed closed. Tom and Astro whirled to see their missing unit mate lounging against the doorframe, grinning broadly.

"Roger!"

"Where've you been, blast you?"

Tom and Astro both jumped forward and spoke at the same time. The blond-haired cadet merely looked at them lazily and then sauntered forward, pulling six small study spools from his pockets.

"You wanted these study spools, didn't you?" he drawled, giving his unit mates three apiece. "Be my guest and study like mad."

Tom and Astro quickly read the titles of the spools and then looked at Roger in amazement. They were the ones the unit needed for their end-term exams, the ones all the cadets needed.

"Roger," Tom demanded, "how did you get these spools? The library was out of them this afternoon. Did you take them from another unit's quarters?"

"I did not!" said Roger stoutly. "And I don't like your insinuations that I would." He grinned. "Relax! We have them and we can breeze through them in the morning and have them back where they belong by noon tomorrow."

"Where they belong!" Tom exclaimed. "Then you have no right to them."

"Listen, hot-shot!" growled Astro. "I want to know where you got these spools and how."

"Well, if that isn't gratitude for you!" muttered Roger. "I go out and risk my neck for my dear beloved unit mates and they stand around arguing instead of buckling down to study."

"This is no joke, Roger," said Tom seriously. "Now for the last time, will you tell us how you got them?"

Roger thought a moment and then shrugged his shoulders. "All right," he said finally. "When I went down to the library to see if it was our turn for them yet, I found that we were still twenty-seventh in line."

"Twenty-seventh?" gasped Astro.

"That's right, spaceboy!" snorted Roger. "So I tried to con that little space doll of a librarian into moving our names up on the list, but just then an Earthworm cadet came in with an order from Tony Richards of the Capella unit, an order for the very spools we needed."

"You mean, you took them from an Earthworm?" queried Tom.

"Well, I didn't take them exactly," replied Roger. "I waited for him out on the quadrangle and I told him he was wanted in the cadet dispatcher's office right away and that I would take the spools on up to Tony."

"And you brought them here!" howled Astro.

"Yup." Roger grinned. "Do you think that squirt will know who I am? Not in a million years. And by the time Tony and the others do find out who has them, we'll be finished. Get it?"

"I get it, all right, you crummy little chiseler," growled Astro. "Tom, we gotta give these back to Tony."

Tom nodded. "You're right," he said.

"Now wait a minute!" said Roger angrily. "I went to a lot of trouble to get these things for you—"

"Look, Roger," Tom interrupted, "I would rather have one night with those spools than a two-week leave in Atom City right now. But the Capella unit is having a tough time making the Spring passing lists. They need those spools more than we do."

"Yeah," said Astro. "We could probably take the tests now and pass, but they really have to study. I'm for getting them back to the Capella unit right now. How about you, Tom?"

The young cadet nodded and turned to Roger who stood there, frowning. "Roger," said Tom, "both Astro and I really appreciate it. But you wouldn't want the Capella unit to flunk out of the Academy, would you?"

Roger gnawed at his thumbnail and then looked at his two unit mates sheepishly. "You're right, fellas," he said. "It was kind of a dirty trick. Give me the spools. I'll take them back to Tony right now."

"Wait a minute!" exclaimed Astro. "It's after hours. We're not supposed to be out of the dorm."

For a second the three boys looked at each other hesitantly. Then, as though they had telepathically conveyed their individual decisions to each other, they turned toward the door. Tom opened it and stepped out into the hall cautiously, then turned back and nodded. Roger and Astro followed him quickly.

As Roger closed the door behind him, he murmured, "There's no reason for all of us to go. I was the one who took the spools, so I should bring them back. Why should you two guys risk getting caught?"

Astro punched him in the shoulder fondly. "We always work together, don't we?" he declared. "If one's gonna get into trouble, we all should."

"Let's go," urged Tom in a sharp whisper, and they all raced silently toward the slidestairs.

Seconds later, the three cadets of the Polaris unit were down in the main hallway of the dormitory building, tiptoeing toward the front portal. Pausing only to look into the O.D.'s office to make sure the officer wouldn't spot them, they reached the portal and ducked out. Pausing again to scan the immediate area for any watch officers, they darted across the slidewalk and into the shadows of the shrubbery.

Quickly and soundlessly, they raced across the green lawn of the quadrangle toward the dormitory where the Capella unit was quartered. Once they sprawled headlong on the turf and lay still as a watch officer suddenly appeared out of the darkness at the base of the Tower of Galileo. But he walked past without seeing them and they continued on across the quadrangle.

Reaching another clump of shrubbery right opposite the Capella unit's dormitory, the boys stopped and discussed their final move.

"This is getting ridiculous," whispered Roger. "I shouldn't have let you two come with me. But I'm going the rest of the way myself."

"We came this far, Roger," asserted Tom. "We'll go the rest of the way and help you explain."

"And you've got a space-blasting lot to explain."

The three cadets whirled as a familiar voice snarled out of the darkness behind them. They saw three figures, all in cadet uniforms, wearing the insigne of the Capella unit. In the forefront was Tony Richards scowling angrily.

"Tony!" gasped Tom. "What are you doing out here?"

"We were on our way over to your dorm, Corbett," growled Tony Richards. "We saw you three sneaking across the quadrangle."

"Coming to pay us a visit, fellas?" asked Roger blandly.

"You know blasted well why we were coming," snapped McAvoy, the second member of the Capella crew.

Davison, the third member of the unit, stepped forward. "Give us back our study spools," he demanded.

"Take it easy," said Tom in a calm voice. "We were bringing them back to you."

"I'll bet," snapped McAvoy.

"Relax," growled Astro. "Tom said we were returning them. We admit it was a dirty trick, but you haven't lost much time. Half an hour maybe."

"Don't try to cover for Manning, Astro," said Tony heatedly. "It's a shame you two guys are stuck with a bad rocket like Manning in your unit."

"Bad rocket!" exclaimed Roger.

"Now, wait a minute, Tony," Tom said, advancing toward the broad-shouldered cadet. "We are returning the spools, and we apologize for yanking them from the Earthworm. But that doesn't mean we'll listen to that kind of talk about Roger."

"He stole them, didn't he?" retorted Davison.

Roger stepped forward. "Davy, my boy," he said in a low controlled tone, "I don't like that remark. I've got a notion to make you eat that word."

"I don't think you can, Manning," replied the angry cadet.

Tom stepped between them quickly. "Listen, fellows, we don't want any trouble. Here are the spools." He held them out.

"That's what I mean, Corbett," said McAvoy sarcastically. "Manning gets you in trouble and then you and the big boy have to bail him out."

"We've apologized," retorted Astro angrily. "You're getting the spools back. So no more cracks about Roger."

"I can take care of myself, Astro," said Roger.

"Here, take the spools and get back to your dorm," growled Tom. He handed the pile of spools over, but as Tony extended his hands, one of the spools dropped to the grass. No one made a move to pick it up.

"There are the spools," said Tom icily. "Now beat it."

"Let's go," said Davison, leaning over to pick up the spool. "The air is beginning to stink around here."

Red-faced, Roger stepped forward and put his foot on the spool just as Davison reached for it. "That's enough, Davison," he snarled.

"Why, you dirty space crawler—" Davison straightened up and swung wildly. Roger ducked the blow easily, then spun the heavy-set cadet around and pushed him back into the bushes.

Tony Richards stepped forward and Astro turned to him threateningly, but Tom quickly shoved them aside and faced Richards.

"Listen, Tony," he said. "We're all out after hours, and if a watch officer spots us, we've had it. We don't want any trouble." He glanced at Davison, who was being restrained by McAvoy. "We apologize. Now get out of here before we're all logged."

Richards nodded and started to turn to his unit mates when suddenly Davison jerked free and lunged at Roger. The blond-haired cadet was not caught unawares. He stepped aside and threw a quick jolting right straight to the Capella cadet's jaw. Davison staggered back and fell to the ground. He shook his head, jumped to his feet again, and charged back with a roar.

Both Tom and Astro and Tony Richards and McAvoy grabbed at their respective unit mates and tried to restrain them. In the struggle to keep Roger and Davison apart, Astro accidentally pushed Richards to one side.

"What in blazes—!" yelled Richards. He suddenly released Davison and gave Astro a shove that sent the big cadet sprawling. And then, without warning, McAvoy swung at Tom. The curly-haired cadet saw the blow coming a fraction of a second too late and caught it on the side of his head. He fell back into the bushes.

Roger yelled in anger at the sudden attack, and grabbing Davison by the front of his tunic, slammed a hard right into the cadet's stomach. Richards grabbed Roger, holding him around the head and neck, as McAvoy swung at him viciously. Seeing their unit mate pommeled, Tom and Astro charged back and the battle was on. The two units forgot about the watch officers and the strong possibility of being caught and slugged it out in the darkness of the quadrangle. The fight seemed to be the climax of a long-standing feud. The Polaris crew had first come to grips with Richards and his unit mates when they were assigned to the old rocket cruiser Arcturus. When the ship was scrapped, the cadets were transferred to the Capella, but the rivalry continued stronger than before. Time and time again, the two crack units had competed for hours on the athletic fields, in space flight tests, and in the classroom. The Polaris unit had constantly come out ahead, often by no more than a fraction of points, but their superiority was clear, and the Capella unit could not repress its resentment and jealousy.

Tony Richards and Tom had squared off and were boxing with lightninglike thrusts of their fists, each waiting for an opening. In back of them, Roger and Davison were simply hammering away at each other's mid-sections, and Astro and McAvoy were rolling around on the ground like bears, growling and tugging. It was brute strength against brute strength.

Tom danced away from Richards' rapierlike left, weaved low, and shot a hard right to his opponent's stomach that left him gasping. Richards doubled over and stepped in to bring up a solid right, then hesitated. Richards was through. The blow to the mid-section had taken all the fight out of him. Tom refused to pursue his advantage while the other could not fight back. His anger cooling rapidly, Tom realized that the whole fight was nothing more than a misunderstanding. As Richards sank to the grass helpless and gasping for breath, Tom turned to break up the other two fights. But Roger was just finishing his battle with Davison. Feinting to the mid-section and pulling Davison's guard down, Roger hooked his left cleanly to the jaw, following immediately with a haymaker right. Davison dropped to the turf, out cold.

Meanwhile, Astro had rolled on top of the last cadet of the Capella unit, and with his great strength, clamped McAvoy's arms to his side. Face to face, the two cadets glared at each other. The muscles tightened in Astro's arms, and beads of sweat popped out on his face.

"Give up!" demanded the Venusian, tightening his grip.

Slowly McAvoy sagged under the pressure Astro was applying and his face began to redden.

"He'll break his back," whispered Roger to Tom.

Tom nodded and stepped forward. "Let him go, Astro. He's finished."

Astro did not let go. His face was white with anger. McAvoy bent further back. "Give up," demanded Astro.

"Grab him," said Tom to Roger. "Get him off Mac before he breaks his back."

Tom and Roger jumped to Astro's side and each grabbed one of the powerful arms encircling McAvoy. It took all their strength to break the viselike hold the giant Venusian had on the other cadet, but slowly they pulled the muscular arms back and McAvoy slumped to the grass.

The three victorious cadets paused and looked down at the beaten Capella crew, then looked at each other.

"Well," sighed Roger, "I suppose that the least we can do now is get them back to their dorm."

Tom and Astro nodded. As the three boys started forward they were stopped by a voice behind them—a voice that roared like an atomic blast.

"Stand to!"

Whirling around in surprise for the second time within a space of ten minutes, Tom, Astro, and Roger saw a menacing sight standing behind them, his balled fists jammed on his hips, his booted legs widespread, and his massive head thrust forward. It was Major Lou Connel, more familiarly known as "Blast-off" Connel, a Senior Line Officer of the Solar Guard and the sternest disciplinarian in the whole Academy. Behind him stood a short, thin man, whom none of the boys recognized.

Connel stepped forward slowly and menacingly, glaring at the three boys.

"Out a little late, aren't you, boys?" he asked with a mildness that sent a chill down their spines.

"Y-yes sir," replied Tom, a slight tremor in his voice.

"On official business, I presume?" The major's voice was still as smooth as silk.

Tom gulped and then shook his head. "N-no, sir," he quavered.

Connel's eyes widened in mock horror. "Why, Corbett," he exclaimed, "didn't anyone ever tell you the rules of Space Academy? Or perhaps you didn't know what time it was?"

Tom bit his lip. He knew that he and his unit mates were caught in a hopeless trap and that Connel was simply baiting them. "I knew what time it was, sir," he said. "We're out after hours."

Suddenly there was a movement in the brush behind Tom as McAvoy stumbled to his feet. Richards also sat up groggily.

"Major!" It was the man behind Connel who spoke. "Who are they?"

As though in answer, Davison stood up too and the three members of the Capella unit were suddenly and horribly aware of the presence of Connel. They immediately braced themselves, their faces white with sudden fear.

"So!" Now the major's voice began to roar again. "Fighting, eh? Well, now we really have something here."

"Sir," began Richards tremulously, "if you'll let us explain—"

"I'll let you explain all right," thundered Connel. "Out after hours, fighting, you'll have a great time explaining to an inquiry."

"An inquiry!" Tom exclaimed involuntarily.

"Did you expect anything less?" roared Connel. "You are all under arrest and confined to quarters."

The six cadets all trembled but said nothing, standing at rigid attention, eyes straight ahead.

"Return to your quarters immediately."

As one, the cadets wheeled and marched off. Tom, Astro, and Roger walked across the quadrangle back to their dorm, and the Capella unit took the slidewalk that led to their quarters. Connel watched them go, a ferocious scowl on his craggy features.

"Little rough on them, weren't you, Major?" asked the man who stood beside the Solar Guard officer.

"Rules are meant to be obeyed, Professor Hemmingwell," retorted Connel stiffly.

"Perhaps you're right," mused the stranger. "But what's this about an inquiry?"

"A trial, Professor. A trial conducted by the cadets themselves to see whether or not the accused should be kicked out of the Academy."

"Kicked out?" exclaimed the professor. "You certainly do believe in discipline."

"These boys are to be Solar Guardsmen," replied Connel shortly. "If they can't obey orders now, they never will."

"Well, it's all very unimportant really, Major," Hemmingwell said with a shrug. "We have many more vital things to think about now than mere cadets. Shall we go? Commander Walters is waiting for us."

As the little man in civilian clothes walked away, Connel stifled a blistering retort. True, his mission here at the Academy was of great importance. But cadets were important too. And he was afraid. The Polaris unit was in grave trouble, grave enough to cause expulsion from the Academy.