Then the young cadet saw the invading spaceship move away from the area around the tower toward the horizon not too far away on the small planetoid. He followed it with his eyes and saw it suddenly land near a cluster of white prisoner huts. Tom gasped as the reason for the attack became clear.

"Major! Major! Major Savage!" he called as he raced across the field. But the major was nowhere to be seen. A guard carrying a medical kit hurried past him and Tom grabbed him by the arm.

"Major Savage! Where is he?"

The guard pointed to a near-by stretcher and Tom saw the unconscious figure of the major sprawled on the plastic frame.

"But—but the prisoners are getting away!" yelled Tom.

"I can't do anything about it. I've got wounded men to care for!" The man jerked away and disappeared in the smoky, choking dust.

The curly-haired space cadet, his face blackened from the smoke, his lungs crying for fresh air, started across the blast-pitted field, looking for help. But there was none to be had. Suddenly he wheeled in the direction of the spaceship and started to run toward it.

As soon as the young cadet had left the smoking area around the wrecked tower, he realized that it was the only section of the small satellite that had suffered attack. Ahead, he could see the prisoners in their white suits crowding around the stabilizer air lock of the invading ship.

Tom dropped to his stomach and watched the knot of men. Suddenly the air-lock portal slid open. There was a loud cheer and the prisoners began scrambling aboard.

Tom knew he would have to move fast. Taking a dangerous chance, he rose to a half-crouch and dashed to one of the small white huts only a hundred feet away. With a final glance at the thinning crowd of escaping men around the ship, he ran straight for an open window, diving headlong through it.

Inside, Tom waited breathlessly for a shout or warning that he had been seen, but none came. He glanced through the window and saw that only seven or eight men remained outside the port. He turned away quickly and began searching the hut.

He found what he was looking for rolled up on the bed where its owner had used it as an extra pillow. He shook out the prison suit of white coveralls, stripped off his own blue cadet's uniform, and hurriedly put on the distinctive prison gear. It was a little large for him and he rolled up the sleeves and trouser legs, hoping no one would notice in the excitement. Then, with a deep breath, he stepped out of the hut into full view of the prisoners still left at the air lock.

"Hey, wait for me!" he yelled, running for the ship.

The men paid no attention in their haste to get aboard the ship. When Tom reached the air lock, there were only two left. He slapped the nearest man on the back.

"Pal, I've been waiting for this a long time!"

"Yah," the man answered, "me too!" Then he looked at Tom closely. "Say, I've never seen you around here before!"

"I just got in on the supply ship last week. They kept me in the tower for a while," Tom replied.

"Oh, well," said the man, "they ain't keepin' anybody there anymore!"

"Come on you guys," snarled a heavy-set man in the air lock above them. "We ain't got all day!"

Tom looked up, and without being told, he felt he was looking into the face of Bull Coxine. And when the other prisoner spoke, he was certain.

"Yeah, Bull," said the man. "Comin', comin'!" He reached up and Bull grabbed his outstretched hand. When Bull pulled, the man literally leaped through the air into the air lock.

"All right, space crawler," roared Bull to Tom, "you're next!" The big man stuck out his hand. Tom gulped. For one desperate second he thought of turning and running away.

"Well?" growled Bull. "You coming or ain't cha?"

"You're blasted right I'm coming," said Tom. "This is one time the Solar Guard is taking it on the chin. And, crawler, am I happy to see it!"

He grabbed Bull's hand and was lifted as easily as if he had been a feather. Coxine dropped him on the deck and turned away without a word to disappear inside the ship.

As he looked around, Tom suddenly felt a cold shiver run through his body. He felt as if he had signed his own death warrant. There was no mistake about it. The ship was the same one he had watched night after night at the exposition on Venus. And the names of the two owners exploded in his brain. "Wallace and Simms!"

He turned to jump out of the air lock, but it slid closed in front of him. He was trapped.

Sprawled on the ground in front of one of the white houses near the tower perimeter, Captain Strong stirred, shook his head, and painfully rose to a half-crouch. With eyes still dulled by shock, he looked around to see Astro lying unconscious a few feet away. His brain still reeling from the effects of Coxine's sneak attack, he staggered over to his knees beside him.

"Astro, Astro—" Strong called. "Astro, snap out of it!"

The big Venusian moaned and opened his eyes. He sat bolt upright. "Captain Strong! What happened?"

"I'm not too sure, Astro," said Strong. "All I remember is Coxine slugging me."

As they struggled to their feet, they suddenly noticed the towering columns of smoke rising into the air.

"By the rings of Saturn!" gasped Strong. "Look, Astro!"

"Blast my jets!" cried the big cadet. "What—what could have happened?"

The two spacemen stood gaping at the shattered remains of the tower and the smoldering area around it. In the distance, scarlet-clad guardsmen moved dazedly around the wreckage and above them a rocket destroyer was blasting on one jet, coming in for a touchdown.

"Astro," said Strong grimly, "I don't know how it could have happened, but the prison asteroid has been attacked. A rocket-blasting good job of it! Come on! We've got to get over there!"

"Yes, sir," said Astro. As they started running toward the field, he searched the figures moving about in the distance for two familiar blue uniforms. "I don't see Roger or Tom, sir," he said hesitantly. "Do you think—?"

"We'll just have to wait and see," interrupted Strong grimly. "Come on, step it up!"

As the two spacemen approached the smoking ruins of the underground cradles, ammunition dumps, and repair shops, they passed groups of men digging into the rubble. In sharp contrast to the careful scrutiny they had received when they first arrived at the prison, no one noticed them now. Strong stepped up to a man in a torn and dirty sergeant's uniform.

"What happened?" he asked.

The man turned and looked at Strong and Astro. Aside from the swollen bump on the Solar Guard captain's head and the bruise on the cadet's neck there were no signs of their having been in the attack. When the guardsman finally replied, there was a sharp edge to his voice. "I thought everyone knew we were attacked, sir!" He turned back to a detail of men who were watching. But Strong pulled the man up sharply.

"Attention!" he barked. The sergeant and the crew came to stiff attention. Strong stepped forward and looked the guardsman straight in the eye. "Under any other circumstances, Sergeant," snapped Strong, "I'd have your stripes and throw you in the brig for your insolence! Now I want a clear account of what happened. And I want it blasted quick!"

"Yes, sir!" stammered the guardsman, realizing he had gone too far. He hurriedly gave a detailed description of the battle, ending with a report that Major Savage had been injured and that Lieutenant Williams was now in command of the prison.

"Where will I find Lieutenant Williams?" asked Strong.

"At the rocket destroyer, sir. It just landed."

"Very well, Sergeant!" said Strong, adding in a gentler tone, "I realize you've had a rough time of it, so we'll forget what just happened. Get back to your work."

As Astro followed the Solar Guard captain toward the rocket ship he saw a familiar figure standing near the air lock. A boy with close-cropped blond hair and wearing cadet blues.

"Roger!" yelled Astro joyfully. "Captain Strong, look! It's Roger!"

They quickened their pace and were soon beside the small space vessel that had been blasted out of commission before it could fire a shot. While Roger was telling them of having volunteered for radar operations aboard the ship and of their being disabled by a near miss, Lieutenant Williams suddenly appeared in the air lock and saluted smartly.

"Major Savage has been injured, sir," said Williams. "Since you are the highest ranking officer on the asteroid, are there any orders?"

"I'm not acquainted with your men, or your prison, Williams," replied Strong. "I'll accept the command as a formality but appoint you my chief aid. Carry on and do anything necessary to get things cleared away."

"Very well, sir," said Williams.

"Have communications been destroyed?"

"Yes, sir. Communications was located in the tower, but Cadet Manning has converted the equipment on ship for long-range audio transmission."

"Very good!" said Strong. "As soon as you get a chance, I want you to make out a full report on the attack, including your personal opinion of who attacked us and why."

"I don't know who manned that ship, sir," said Williams, "but I can tell the reason all right. Every prisoner on the asteroid has escaped!"

"Yes," mused Strong. "I thought that would be the answer. But how did that ship get through your defenses?"

"Captain Strong," said Williams grimly, "I don't think there is any question about it. Someone broke the asteroid code. The attacking ship identified itself as the regular supply ship."

"A Solar Guardsman?" asked Strong.

"No, sir," said Williams. "I'd bet anything that none of our men would do that!"

"Then who?" asked Strong.

"Only one man would be smart enough to get the code and break it, and then sneak it off to the attacking ship!

"Who?" asked Strong.

"Bull Coxine!" answered the young officer through clenched teeth.

They were interrupted by a guardsman. "Sir, we found this in prison hut twenty-four."

"What is it?" asked Strong.

Astro's eyes suddenly widened and he stepped forward. "Why, that's ... that's Tom's uniform!" he stammered.

"Tom!" gasped Strong. "But where is he?"

"We've searched the immediate area, sir," replied the guardsman. "Cadet Corbett isn't here."

"Are you sure?" demanded Strong.

"Yes, sir," said the guardsman stoutly.

Strong took the uniform and examined it carefully. Then he turned to Roger and snapped, "Prepare the audioceiver for immediate transmission to Space Academy, Manning. Astro! Get aboard our ship. Check her for damage and let me know how soon we can blast off!"

The two cadets saluted and raced for the small spaceship.

Thoughtfully holding Tom's uniform in his hand, Strong turned back to Williams. "I'm going to leave as soon as I can, Williams. I'll tell Space Academy about the attack and see that a relief ship is sent out to you right away. Meantime, I'm leaving you in command." He paused and looked at Tom's uniform again. "If Cadet Corbett isn't on the asteroid, he must be on the attacking ship with the prisoners. The only question now is, do they know it?"

"You mean he smuggled himself aboard?" asked Williams.

"I'm almost sure of it!" said Strong. "And if he is, he's going to try to get some sort of message out. I've got to be ready to pick it up."

Strong paused and looked up at the sky overhead, still thick with smoke. "And if he does ask for help, I'm going to answer him with the biggest fleet of spaceships he'll ever see in his life!"