Another guard went down in the scuffle and O'Toole howled his battle cry
again.

* * * * *

Harror was silent. Blake changed his position wearily, waiting for some
sign. He heard Harror breathing loudly from the far corner. The blow on
the face must have dazed him.

Blake closed it slowly, listening to Harror. Waiting for him to strike
again. Then two giant arms closed tightly around his chest, cutting off
his breath. He tried to shout, but his lips made no sound. He felt
himself sinking toward the floor, Harror on top of him. Harror was
holding on with all his strength.

Blake relaxed slowly, and his head fell to one side. He felt the grip
relax just a trifle, and gathered all his remaining strength. With a
terrific uppercut, Blake's arm shot upward, catching Harror squarely on
the chin. There was a sudden snap as the giant's head tipped back as
though unhinged. His arms relaxed and Blake fell away from him.

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."

* * * * *

A quick knock came on the door. Blake said, in a hard voice.

"Yeah! Who is it?"

"Slater," was the reply. "Tell the boss we got the train cleaned out.
We're all ready to set it loose."

In the light of the open door, Blake looked at O'Toole. The Irishman was
already in one of the Silver Mask uniforms. His face was hidden and he
looked like one of the gang.

"Tell him the boss will be all set in a minute," Blake said. "I've got
to get into one of these outfits."

O'Toole flung the door open wider and