"What's that noise, Tom?"

The two cadets were walking through the tunnel when they heard the strange booming roar. Behind them, Sinclair overheard Roger's whispered question and laughed. "That is the sound of the slaves being fed their lunch. They do not know yet that there has been a battle and soon they'll be free!"

"Slaves!" gasped Roger. "What kind of slaves?"

"You shall see. Keep going!" Sinclair prodded the cadets with his ray gun. The tunnel had grown larger and the downward slant of the floor lessened as they pressed forward. The noise ahead of them grew louder and stronger and now they could distinguish occasional words above the din.

"We must pass through the big vault where the slaves are working," said Sinclair. "I would advise you to keep your mouths shut and do as I say!"

Neither Tom nor Roger answered, keeping their eyes straight ahead.

The tunnel suddenly cut sharply to the right and they could see a blaze of light in front of them. The two boys stopped involuntarily, and then were nudged forward by Sinclair's guns. Before them was a huge cavern nearly a thousand yards high and three thousand yards across, illuminated by hundreds of torches. Along one side of the cave a line of men were waiting to have battered tin plates filled from a huge pot at the head of the line. The men were in rags, and every one of them was hardly more than skin and bones. At strategic places around the cavern, Nationalist guards kept their guns trained and ready to fire. They brought up their guns quickly as Tom and Roger entered, and then lowered them again as Sinclair appeared. Every eye turned to the Nationalist leader as he marched across the floor of the cave, Tom and Roger walking before him.

"You see," said Sinclair, "these wretched fools thought my organization was a utopia until they learned that I was no better for them than the Solar Guard. Unfortunately they learned too late and were sent here to dig underground pits for my spaceships and storage dumps."

The small column of three marched across the floor of the cave toward another small tunnel on the opposite side. The slaves were absolutely still, and the guards smiled a greeting at their leader when he passed them.

Sinclair ignored them all. "Beyond that tunnel," he continued, pointing to the small opening ahead of them, "there is a spaceship. We will board that ship and blast off. The three of us. Where we will go, I haven't decided yet. Perhaps a long trip into deep space until the Solar Guard has forgotten about you and me and the Nationalists. Then we will return, as I said before, to Mars, or perhaps Ganymede, and I will start all over again."

"You're mad!" said Tom through clenched teeth. "Crazy as a space bug!"

"We shall see, Corbett. We shall see!"

Suddenly Roger broke away and raced toward the mass of slaves. He shouted wildly, "Get the guards! The Nationalists are beaten! The base in the canyon has been destroyed! Hurry! Rebel!"

The emaciated men milled around the cadet, all asking questions at once.

Sinclair signaled to the guards. "Shoot him down!" Four guards took careful aim.

"Roger! Look out!" warned Tom.

Roger whirled around in time to see the guards about to fire. He dived for a mound of dirt and hid behind it. The energy shock waves licked at the sand where he had stood a second before. Roger got up and ran for better cover, the guards continuing to fire at him. Then, around the cadet, the slave workers began to come alive. Some hurled stones at the guards, others began climbing up the sides to the ledges where the guards stood. Taking in the situation at a glance, Sinclair shoved the ray gun in Tom's back and snarled, "Get going!"

The young cadet had no alternative. He turned and marched hurriedly across the floor toward the small tunnel ahead of him. Several slave workers tried to attack Sinclair, but in their weakened condition, they were no match for the alert Nationalist leader who froze them instantly with his paralo-ray gun.

Roger saw Tom heading for the tunnel and made a sudden dash for Sinclair. But the rebel leader heard the pounding of footsteps and turned to fire at Roger as the cadet sailed through the air in a flying tackle. The jolting ray hit him squarely and he landed on the ground with a thud a few feet from Sinclair, completely immobilized again.

Tom tried to seize the momentary advantage, but once again Sinclair was quicker and forced Tom back into the small opening of the tunnel.

Around them, the slave workers were being whipped into a frenzy after months of stored-up hatred for their guards. Hundreds of them were climbing up toward the guards' posts, unmindful of the deadly fire pouring down on them.

"Get in there quick!" demanded Sinclair. He shoved Tom through the small opening, and after a quick glance over his shoulder at the surging slaves, followed the cadet.

Sinclair flashed a light ahead of them and Tom saw the reflection of a bright surface. In the distance he recognized the outlines of a spaceship.

"Keep moving!" ordered Sinclair. "You're my protection in getting out of here, and if I have to freeze you and carry you aboard, that's just what I'll do! Now get moving!"

Tom walked to the air lock of the ship, Sinclair right in back of him. The rebel leader pressed an outside button in the ship's stabilizer fin and the port swung open slowly. "Get in!" growled Sinclair.

Tom stepped into the ship and waited. Sinclair climbed in in back of him and closed the air lock.

"Through that hatch," said Sinclair, motioning toward the iron ladder, "and keep your hands in the air."

"How do you think you're going to get through the Solar Guard fleet that's standing off above the canyon?" asked Tom casually. "As soon as they see this ship blast off, you'll have a hundred atomic war heads blasting after you!"

"Not as long as I have you!" sneered Sinclair. "You're my protection!"

"You're wrong," said Tom. "They'll open fire, anyway."

"That's the chance I've got to take," said Sinclair. "Now climb up to the control deck and get on the audioceiver. You're going to tell them you're aboard!"

Tom walked ahead of the rebel leader toward the control deck, his mind racing. He knew that Sinclair was going through with his plan and he also knew that the Solar Guard would not pay any attention to anything he had to say. If, after three warnings, Sinclair didn't brake jets and bring his ship to a stop, he would be blasted out of space. He had to do something.

"Where's the communicator?" asked Tom.

"Over by the radar scanner." Sinclair eyed him suspiciously. "Remember, Corbett, your life depends on this as much as mine. If you don't convince them you're worth saving by letting me get away, you're a dead pigeon!"

"You don't have to tell me," said Tom. "I know when I'm licked."

Sinclair took his position in the pilot's chair, facing the control panel. For a brief moment his back was to Tom as he bent over to turn on the generators. Tom took a deep breath and lurched across the deck. But Sinclair turned and saw him coming, and jerked up the ray gun. He wasn't able to get clear in time. Tom's fingers circled the barrel of the gun as Sinclair fired. The barrel grew hot as Sinclair fired repeatedly. Tom's fingers were beginning to blister under the intense heat, but he held on. With his other hand he reached up for the rebel's throat. Sinclair grabbed his wrist and, locked together, they rolled around on the deck.

Sinclair continued to fire the ray gun and Tom's fingers were burning with pain from the heat. Suddenly the cadet let go the gun, spun around, and jerked Sinclair off balance. He swung his free hand as hard as he could into the rebel's stomach. Sinclair doubled over and staggered back, dropping the gun. Tom was on top of him like a shot, pounding straight, jolting rights and lefts to the man's head and stomach. But Sinclair was tough. He twisted around, and quick as a cat, jumped to his feet. Then, stepping in, he rapped a solid right to Tom's jaw. The cadet reeled back, nearly falling to the deck. Sinclair was in on top of him in a flash, pounding his head and body with vicious smashing blows.

Tom fell to the floor under the savagery of the rebel leader's attack. Sinclair lifted his foot to kick the cadet as Tom's fingers tightened around the barrel of the discarded ray gun. He brought it up sharply against the planter's shin and he staggered back in pain. Tom took careful aim. He fired the gun. Nothing happened. The gun was empty.

Sinclair rushed the cadet again, but Tom stepped aside and swung the heavy gun with all his might. The metal smashed against Sinclair's head and he sank to the deck, out cold.

The last rebel of Venus had been defeated.

"We found Roger trying to keep the slaves away from the guards," said Strong. "They were ready to tear them apart!"

"Can't say that I blame them," snorted Connel. "Some of those poor devils had been working in the caves for three years!"

Tom, Roger, and Astro sat sprawled in chairs in one of the offices of the Nationalist headquarters listening to Strong and Major Connel sum up the day's battle. The entire army of Nationalist guards, Division Chiefs, and workers had been rounded up and put aboard the troop carriers to be taken to a prison asteroid. Each individual rebel would be dealt with under special court proceedings to be established by Solar Alliance decree later.

"There are still some things I don't understand," said Astro. "How did they know you were going to investigate them in the first place?"

"After our meeting with Commander Walters," said Connel, "we sent a special coded message to the Solar Alliance Delegate here on Venus. His secretary intercepted the message, used stolen priorities for himself and two assistants to get to Earth and back on an express space liner without being missed."

"The secretary!" shouted Tom. "That's the same fellow I saw in Atom City when we were bumped out of our seats on the Venus Lark!"

Roger looked up at Tom with a scowl. "A fine time to remember!"

Strong grinned. "We discovered him, Tom, when that attempt was made to kidnap you by the cab driver. We also picked up the owner of the pawnshop."

"The most amazing thing about this space joker, Sinclair," commented Connel, "was the way he had everyone fooled. I couldn't figure out how he was able to get around so quickly until I learned about those buildings."

"What buildings?" asked Tom, suddenly remembering how the rebel leader had disappeared so quickly and quietly when he was being held captive with Mr. and Mrs. Hill in the Sinclair home.

"Every one of the important members of the organization, the Division Chiefs, they called themselves, had a small shack on his property near the edge of the jungle. It was nothing more than a covering for a shaft that led to a tunnel, which, in turn, led to other tunnels under the jungle and eventually connected with one leading right into the base."

"You mean," said Astro, "they have underground tunnels all through the jungle?"

"That's right," asserted Connel. "If they had been prepared for our attack, they could have beaten the pants off us. Not only in space, but on the ground. They could have run circles around us in those tunnels. I got suspicious when I found a hut at the Sharkey place with no windows in it."

"Say, remember the time Sinclair barked at me for going near that shack on his place when we first arrived?" said Roger.

Connel grinned. "I'll bet you a plugged credit that if you had opened that door you'd have been frozen stiffer than a snowman on Pluto."

"Well, anyhow," said Tom happily, "we got what we came after."

"What was that?" asked Strong.

"A tyrannosaurus!" replied the curly-haired cadet.

"And that's another thing," said Connel. "That tyrannosaurus we killed was a pet of the Nationalists. I don't mean a household pet, but it fitted into their plans nicely. The tyranno's lair was near the top of that canyon. Any time a stray hunter came along, the tyrannosaurus would scare him away. So when you three came along and said you were deliberately hunting for a tyrannosaurus, they got worried."

"Worried?" asked Roger. "Why?"

"They thought you were actually hunting or investigating them, and when I started nosing around, they were sure. That's why Sinclair ordered his boys to burn down his plantation—to try to throw us off the track. So you see," Connel concluded, "your summer leave really started the ball rolling against them."

"Summer leave!" shouted Roger. "What day is it?"

"The twenty-ninth of August," replied Strong.

"Oh, no!" moaned the blond-haired cadet. "We start back to class in three days!"

"Three days!" roared Astro. "But—but it'll take three days to write up our reports of everything that's happened! We won't have any time for fun!"

"Fun!" snorted Connel. "Fun is for little boys. You three space-brained, rocket-headed idiots are spacemen!"

A hyperlinked "Table of Contents" has been added.

The following typos were corrected.