like to know where that track ends."

"You will." Blake went toward the door. He gripped O'Toole's shoulder. "You're a good Irishman, O'Toole. Now go out of here and straight to the cab. I don't think they'll dare send one of the other men. If the controls are tied into place, leave them alone. When I signal, set all motors going full speed. Sit tight and keep her flying."

"And the end of the track?" O'Toole asked. "If I don't get shot in the back before I'm half way across the cave, how do I know when to stop?"

Blake chuckled dryly.

"Perhaps you won't," he admitted. "But I'll be in the rear lounge with every male passenger within my sight. One of them is bound to break down when he knows he's at the end of the trail."

"So?"

"I'll jerk the emergency cord," Blake said. "Set your brakes the minute you hear it. O'Toole, it's a long chance but we've got to take it."

"One more thing," O'Toole asked. "Blake, who in hell is the leader of the Silver Masks?"

Blake hesitated, his face darkening. He opened the door and pushed O'Toole out gently.

"If I'm not mistaken," he whispered evenly, "Walter Ferrell knows more about this than he's telling."

The gang of Silver Masks were gathered around the front end of Mono 6 as Holly O'Toole and Jeff Blake emerged from Harror's office. They walked swiftly toward the cab, and Slater who had evidently been waiting, stepped from the crowd and came toward them.

"How about it?" He addressed Holly O'Toole, as O'Toole seemed to be leading Blake. "Everything has been stripped from the baggage cars. She's ready for her trip into the lake."

"Okay!" O'Toole mumbled. He turned to Blake. "Take two men and get all the passengers into the lounge car."

Blake's heart was pounding wildly. If O'Toole slipped now, they'd all pay for it. He turned toward the crowd of waiting masked men.

"Two of you guys step out," he ordered. "Open the doors and herd those cattle into the last car back."

They obeyed him instantly. In five minutes every man and woman in the flyer were crowded into the car with Walter Ferrell and Dauna. O'Toole hesitated, started to climb into the cab of Mono 6, and Slater stopped him.

Standing a few feet away, Blake heard them mumble something. O'Toole pointed to Blake.

"I'll see that she gets clear of the cave," he said in a loud voice. "The boss wants him to be in the car until it's started and on the way down."

Slater hesitated, nodded and turned away. O'Toole winked and Blake grinned back at him. The Irishman had done a swell job. This was one night when his blarney had been a blessing.

When Jeff Blake went into the lounge car, he drew his electro gun. The car was full of frightened women and angry men. He was afraid they might turn on him in the Silver Mask, and spoil his plans. Slater had followed him to the door.

"Don't stick too long," the man cautioned him. "You'll be doing a hundred miles an hour before you hit the head end of the valley. The boss is going to jump when he leaves the cave."

The boss? Then O'Toole really had done a good job. Automatically Blake looked toward Walter Ferrell, and noticed that he was of the same build and size as O'Toole. Slater couldn't see the occupants of the car, but he guessed who Blake was staring at.

"Take good care of Ferrell," Slater said in a dry whisper. "He's worth a lot of money to us."

Blake grinned.

"Don't worry," he said. "I'll take good care of him."

Mono 6 started to glide smoothly back out of the cave. Somewhere out of sight behind the flyer, a huge door opened in the side of the mountain and screeched its way into the concealed slit above. The train gathered speed swiftly, and the moon suddenly appeared from nowhere. Blake waited, made sure there were no guards remaining on board. Then he ran swiftly toward the group around Ferrell. He ripped the mask off as he moved, and Dauna, her eyes glued to his face, gasped in happy surprise.

"Jeff," she ran toward him, "Oh! Jeff, I'm so glad."

He pressed his lips to hers quickly, turned away without a word and faced Walter Ferrell. Ferrell's face was expressionless, frightened.

"Jeff Blake," he said. "How did you make it?"

"There isn't time to talk now," Blake answered quickly. "O'Toole and I overcame Harror. We managed to get them to start Mono 6 out of the cave. O'Toole is in the cab now. In a few minutes we'll be free. Before they wake up to the trick we played on them we'll be five hundred miles away."

Ferrell's face relaxed. Although Blake watched him closely, the man showed no sign of alarm.

"Good work, boy." His hand gripped Blake's shoulder. "I don't know how you did it, but there'll be a big reward for you when we reach South Station."

Blake sat down opposite him. His eyes never left Ferrell's face. Yet, Ferrell held himself remarkably in reserve.

"I did it more for Dauna than anyone else," Blake admitted slowly. "We wouldn't have anything happen to her would we?"

Ferrell turned toward his daughter.

"I've been pretty hard on my girl," he said. "But if she hadn't got out safely I'd have torn that place apart with my bare hands."

He meant every word of it. Blake's body tensed. The full shock of what Ferrell's words meant was sinking slowly into his brain. Suddenly he shot to his feet.

"I've been a fool," he said. "A damned, blind fool!"

"A fool?" There was no mistaking Walter Ferrell's bewilderment.

Blake was already at the car door.

"I'm going to take a long chance," he shouted back. "Ferrell, you crowd the passengers into both halls at the ends of the car. Open the outer doors. If the train goes into the lake, try to get as many out as you can."

With the shouts of alarm still ringing in his ears, Blake went swiftly through the long empty cars toward the cab. The train was backing through the night now at a terrific speed, and the black forest flashed past him as he went to his appointment with Holly O'Toole.

Blake reached the head car, tried the door and stepped back in alarm. It was locked. He looked overhead and found the tiny emergency entrance to the catwalk above. Back inside, he dragged several chairs out quickly, climbed them and pushed upward. Luckily the door was open. Head and shoulders above the train, he stopped. The wind pushed him back, clutching at his breath. He climbed out on the catwalk slowly, crouching to the smoothness of the plastic, and wriggled ahead.

The diesel room was below him now. Its top door opened easy. He listened. All motors were purring smoothly. The hot smell of oil drifted up. Ahead, the cab was silent.

He pushed his feet down cautiously and dropped. His feet hit the oily floor and he fell flat. The door to the cab was open. He went toward it, saw lights over the dash and ran to the main control stick. It was lashed firmly in place with heavy chain.

The speed indicator was pointing to four hundred miles per hour. Swiftly he released the chain, and felt the control lever break loose, falling into neutral. Blake reached for the magnetic brake, and heard a footstep on the floor behind. He whirled swiftly. O'Toole was standing at the entrance of the diesel room, electro gun pointing at Blake's chest.

"You're a smart one," O'Toole said. He waved the gun meaningly. "I'm glad you cut the power. We'll coast from here to the lake."

Blake was silent.

"Thought Walter Ferrell was the chief of this outfit, did you?" O'Toole was enjoying himself. "Well, I didn't have any idea of jumping the train. We'll coast within a mile of the cut, shoot the coupling free between the cab and the coaches, and set our brakes. Walter Ferrell and his little party are going to taste cold water for the last time."

Blake said nothing. He started to walk deliberately toward the hulking Irishman. O'Toole snarled.

"Back," he warned. "I've got to kill you anyhow. It might as well be now."