The streets of Olympia echoed to the thunderous roar of jet trucks and jet cars racing to sector twelve. Miners, Solar Guardsmen, and Space Marines jammed the vehicles, their faces grim with determination as they prepared for an all-out attempt to prevent the death of the colony.

Walters, Strong, and Kit Barnard sat behind Blake, the Space Marine lieutenant, and Sergeant Morgan as they rocketed through the streets. There was little conversation, each man thinking bitterly of Charles Brett and Quent Miles. Walters had already foreseen the possibility of trouble with emotional miners and had ordered Blake to be personally responsible for the safety of Miles and Brett when they were arrested.

"They get a fair trial like anyone else," declared Walters. "And they are innocent until proven guilty by a jury."

Now, as he sat beside Strong, Walters wondered if they would be able to save the city from the ammonia gas. He had taken a calculated risk in ordering guardsmen at the spaceport to aid in this search. If they should fail to find the leak, and the gas death spread farther across the city, the miners and their families would be helpless before it. The thought of the riots that would ensue if the people tried to get aboard the spaceships without order made the hardened commander shudder.

The jet car slowed and finally stopped. "What's the matter?" growled Walters.

"This is as far as we can go in the car, sir," replied Blake. "The gas is so thick I can't see where I'm driving."

"Very well. Put on your masks," Walters announced. "Keep in contact with the spaceport control tower. They'll relay messages to me and my orders back to you. Let's go. Spaceman's luck."

The men opened the doors of the small jet car and stepped out into the swirling mists. Though there were more than a thousand men searching the area, they could not rid themselves of a strange feeling of loneliness as they each walked forward into the mists of death.

Strong and Walters inched their way down the street like blind men, feeling for each step with hesitant feet.

"Are you sure we're heading in the right direction, Steve?" asked Walters.

"Yes, Commander," replied Strong. "The warehouse is located about a half mile down this street."

"Of all the blasted messes," grumbled Walters. "We've got the finest radar system in the universe and we have to walk along here feeling our way like blind men."

"There's no other way, I'm afraid," said Strong grimly.

"Are you still with us, Kit?" called Walters.

"Right here, sir," came Barnard's voice, immediately behind them.

The spacemen continued their slow march through the mist in silence. Once, when Walters stumbled and nearly fell, he roared angrily.

"By the craters of Luna, when I get my hands on those two space crawlers, there won't be enough of them left for a trial!"

"Yes, sir," said Steve. "But if anything has happened to those cadets, you'll have to excuse ranks, sir, and wait your turn."

"Of course!" Walters exclaimed a moment later. "That's what happened to Manning! He didn't run away. He must have gotten on to them during the trip out here and they shut him up."

"Exactly what I was thinking, sir," said Strong, and then suddenly stopped. "I just bumped into a wall. We're here."

Tom and Astro climbed wearily through the trap door into the room above the main shaft while Quent Miles watched them closely, keeping his paralo-ray gun leveled. The two boys hitched the heavy lead boxes into a more comfortable position on their shoulders and started toward the door leading outside. But neither boy thought of his discomfort or weariness now. With the explosive charge safely hidden under Tom's blouse, they had a chance to fight back. It was a small chance, perhaps, but at least a chance.

Outside, they walked slowly through the swirling methane ammonia and Tom edged closer to his unit mate.

"Can you hear me, Astro?" he whispered through the mask amplifier. The big cadet simply nodded, keeping his eyes forward.

"We'll have to bluff our way now," continued Tom in a low whisper. "This stuff has to be set off with a charge of electricity."

"Where do we get it?" mumbled Astro.

"The paralo-ray gun."

"You're space happy. It won't work."

"I know that," hissed Tom. "But maybe Miles doesn't. I'll challenge Miles, hold the stuff right in front of me, and warn him that if he fires he'll set off the explosive and blow the four of us up."

"Oh, brother. That's a bluff to end all bluffs! Suppose he doesn't bite?"

"Then get set to take another paralo-ray charge."

"O.K.," sighed Astro. "When do you want to try it?"

"I'll give you the word," replied Tom. "Just be ready." The cadet turned away quickly. "Watch it," he hissed. "He's suspicious."

The two boys plodded along across the field as Miles moved up closer. He stared at them for a long moment and then continued to walk along directly behind them.

When they reached the ship, Miles allowed them to rest and catch their breath before making the long climb up the ladder to the air-lock portal. Brett suddenly appeared in the open portal above them.

"Hey, Miles," he called, "is that the last of it?"

"Yes," Miles called back. "You get in touch with our pal?"

"Uh-huh. He's going to meet us out in space."

"In space?" Miles stared up at Brett with a strange gleam in his eye. "Why not the hide-out?"

"I don't know," Brett replied from above. "Let's not waste time talking now. Get those other two cases up here. I want to blast off."

Miles turned to the two cadets and waved his paralo-ray gun menacingly. "All right, you two. Get going!"

"Give us a few more minutes, Miles," said Tom. "We're so tired we can hardly move."

"Get up, I said," snarled the black-suited spaceman.

"I can't," whined Tom. "You'll have to give me a hand."

Miles pointed his gun straight at the young cadet. "All right. That means the big fella makes two trips and I freeze you right now."

"No, no!" cried Tom, jumping to his feet. "I can make it. Please don't freeze me again." Astro turned away to hide his smile.

Sneering his disgust at Tom's apparent fear, Miles prodded the cadets up the ladder. Tom went first, the heavy box digging into his shoulder. Astro followed, cursing the fog that prevented him from seeing where Miles stood below him so he could drop the heavy box on him.

Above them, Charles Brett watched them emerge out of the ammonia mist, ray gun held tightly in his hand. Tom climbed into the air lock safely and dropped the box on the edge of the platform, slumping to the deck beside it. Astro followed seconds later, and then Miles.

"Don't stop now," barked Miles. "Put those boxes below with the rest of them."

Tom got up slowly, leaning heavily on the outer edge of the precariously placed box. The box suddenly tilted and then slipped out of the air lock to disappear in the mist.

"Why, you clumsy—" Brett roared, raising his gun menacingly.

Astro stepped in front of Tom. "I'll get it," he cried. "Don't shoot!"

"Go on then," snarled Brett. "Go down with him, Miles. I'll stay here with Corbett."

"You go down with him," sneered Miles. "I've been up and down that ladder fifty times while you sat up here doing nothing."

"Is that so?" cried Brett angrily, turning to face the black-clad spaceman. This gave Tom the opportunity he was waiting for. He pulled the small charge of explosives from his tunic and held it in front of him.

"All right, you two!" he shouted. "Drop those paralo-ray guns. This is the booby trap you planted in the tunnel. You fire those ray guns and we all go up together."

Brett jumped back. Miles took a half step forward and stopped. "You haven't got the nerve," he sneered.

"Shoot and you'll find out," said Tom. "Go ahead! Shoot, if you've got the guts. Get down the ladder, Astro," he said. "They won't fire as long as I've got this in my hand."

Brett had begun to shake with fear but Miles brought his ray gun up slowly. He aimed it at Astro who was starting down the ladder, his head and shoulders still showing in the open air-lock portal. Tom saw what Miles was going to do. "Jump, Astro!" he shouted.

Astro jumped at the exact instant Miles fired. "Rush him," cried Miles. Brett made a headlong dash for Tom, but the cadet side-stepped at the last moment and Brett fell headlong out of the ship, wailing in sudden terror as he fell to the ground.

Miles turned to Tom. He ripped off his mask and with his free hand closed the air-lock portal.

"You fooled Brett, but you didn't fool me, Corbett." He laughed. "It takes a direct electric charge to set that stuff off. You just helped me get rid of a very obnoxious partner." He leveled his paralo-ray gun.

"I hate to do this," he said, "but it's you or me."

He fired. Tom was again frozen into that immobile state more dead than alive. Miles laughed and hurried to the control deck.

Astro got up on his knees slowly. Though the fall had been a hard one, he had rolled quickly with the first impact, thus preventing any injuries. He shook his head, regained his sense of direction, and then rose to his feet, starting back to the ship in hope of helping Tom. He tripped over something and fell to the ground. Groping around in the thickening ammonia gas he felt the still form of a body. For a moment, thinking it was Tom, his heart nearly stopped, and then he breathed a silent prayer of thankfulness when he recognized Charley Brett. He felt the man's heart. There was a faint beat.

Astro opened the valve on Brett's oxygen mask wide and waited until the man was breathing normally. Then he began feeling his way back to the ladder. Suddenly he heard a sound that made his blood run cold. It was the unmistakable whine of the cooling pumps building for blast-off. And he was directly underneath the exhaust tubes.

He scrambled away, heading back to the spot where Brett lay. The whining of the pumps built to an agonizing scream. There were scant seconds left to save himself. He could not wait to find Brett. He began running wildly away from the ship, stumbling, falling, rising to his feet again to plunge on, away from the deadly white-hot exhaust blast of the Space Knight.

There was a terrific explosion, and then Astro was lifted off his feet and hurled through the mist, head over heels. He screamed and then blacked out.

"We found him about a thousand yards away from the warehouse, Commander," said the guardsman. "He looks pretty beat and his clothes are burned a little. I think he must have been caught in the blast of that ship we heard take off."

Walters looked down at Astro's big frame, sprawled on the ground, and then at the medical corpsman who was giving him a quick examination. The corpsman straightened up and turned to Walters and Captain Strong. "He'll be all right as soon as he wakes up."

"Shock?" asked Strong.

"Yes. And complete fatigue. Look at his hands and knees. He's been doing some pretty rough work." The corpsman indicated the big cadet's hands, skinned and swollen from his labor in the mines.

"Wake him up!" growled Walters.

"Wake him up!" exclaimed the corpsman. "Why, sir, I couldn't allow—"

"Wake him up. And that's an order!" insisted Walters.

"Very well, sir. But this will have to go into my report to the senior medical officer."

"And I'll commend you for insisting on proper care for your patients," Walters stated. "But in the meantime we've got to find out what happened. And Cadet Astro is the only one who can tell us."

The corpsman turned to his emergency kit. He took out a large hypodermic needle, filled with a clear fluid, and injected it into the big cadet's arm.

In less than a minute Astro was sitting up and telling Walters everything that had happened. When he told of the pipe that was sucking off the oxygen from the main pumps, Walters dispatched an emergency crew to the mine immediately to plug the leak. Then, when Astro revealed the secret of the mine, the presence of the uranium pitchblende, Walters shook his head slowly.

"Amazing!" he exclaimed. "Greed can ruin a man. He could have declared such a discovery and still had more money than he could have spent in a lifetime."

Walters spun around. "Steve, I want the Polaris ready to blast off within an hour. We're going after one of the dirtiest space rats that ever hit the deep!"