I was afraid you would be asleep. He came late, but he's in the tunnel now."

"Who is it?"

"The fellow we've suspected all along. Poses as an ignorant laborer, but he's not ignorant by a long shot. His name is Hank Norden."

Masters pointed toward a clump of bushes. As he did, he caught the captain's arm with his left hand. The bushes were moving.

A black hole appeared at the base of the bushes and from it emerged the head and shoulders of a man. Taylor drew his pistol. The man's head turned, searching the shadows to see if he was observed. He failed to detect the figures of Taylor and Masters, huddled nearby in the shadows.

The man scrambled from the hole. He closed the trap door behind him and then started to move rapidly away.

"Halt!" barked Taylor.

The man began to run. The captain's pistol spat, kicking up dust beside the running feet. The fleeing man jumped to one side, to spoil Taylor's aim on the next shot, but as he did so, he stumbled and fell.

A moment later Taylor had landed on top of him, pinning him to the ground.

The faded moonlight showed angry eyes, a jutting, undershot jaw and a sharp, pointed nose.

"Damn you!" spat the captive.

Taylor removed a revolver from the prisoner's clothing and tossed it to Masters.

"It's Norden, all right," Masters said, scrutinizing the captive. "I'd know that jaw in a million. What are you doing here, fellah?"

"I'm blowing the factory to hell!" Norden said between his teeth. "You can't stop me. Everything's fixed. In a minute a bomb'll go off. You, I, everyone will be smashed to atoms. And I'm glad. For the fatherland."

"We know why you're doing it," Taylor said. "Come on, Masters. Get your short-wave working. Notify the factory office. Where's the bomb, Norden? Come on, speak up, or I'll pull you to pieces!"

Norden said nothing. Masters was calling the office. He turned to the captain:

"I can't raise anyone."

"We'll go to the gate." Taylor prodded the prisoner ahead on the run.

"You can't make it in time," Norden panted.

"We'll die trying!"

A floodlight turned the area in front of the gate into a patch of daylight. An armed sentry challenged from a small building. The captain answered.

"Sorry, but you can't come in. Strict Orders. After hours," the sentry said, when the captain asked to be allowed to pass.

"But it's urgent--life or death. We've got to use your telephone. Or--you call the office. Tell the super there's a bomb in the plant--"

The sentry's jaws gaped, but only for an instant. Down the road inside the plant came a running, bareheaded figure--screaming:

"Let me out! Let me out of here!"

"Halt!" shouted the sentry.

The figure stumbled to a stop at the gate. The light showed the pale, sweating face trembling with fear.

"What's the matter with you?" the sentry asked.

"The metal pots! They're alive! Big, orange bubbles are floating from the cauldrons!"

"Nuts!" said the sentry. "You're drunk."

But as the soldier spoke there was a trembling movement of the ground beneath the feet of the men at the gate.