The Irishman had done his job well. The room was quiet.

Then: "Jeff, Jeff, are you all right."

Blake chuckled.

"I've got condensed ribs," he said. "But I think Harror will lie still for a while."

"Golly!" O'Toole sighed in relief. "You sure had a Goliath on your hands. Wish I could have helped you."

"What became of those two guards," Jeff asked? "Seems to me they had you on the spot for a while."

"Aw!" O'Toole said. "I got hold of one of them fire guns and there wasn't anything to it."

Blake had reached the door to the outer cavern. He opened it a couple of inches and looked out. The Silver Mask gang were still working on Mono 6.

Even as he watched, a man detached himself from the gang at the far end of the train and came slowly toward the partially opened door. Blake jumped back and closed it tightly.

"Get two of these guards out of their uniforms," he said. "Make it quick. We've got more trouble coming."