l under way an hour later when a
couple of Mantor's men joined their chief, who stood with a somewhat
bruised Marc Polder and an unharmed but furious Lee Treynor. Between
them they carried a small, obviously heavy box.

"You know what this stuff is, boss?" one of the men asked. "They got a
hundred or a hundred-fifty boxes like this in there." He nodded at the
Navy warehouse.

They set the box down and Mantor flung back its lid. It was filled with
small grey pellets. Mantor picked up a handful and stood fingering them.

"Looks like rocket fuel," he said. "Only I've never seen any this color.
And it's too heavy, also." He turned to the comptroller. "_You_ tell me
what it is."

Marc shrugged. "I don't know. It's a Navy secret."

Mantor's eyes glinted. Without warning his fist flew out, sent the
comptroller sprawling in the dust where he lay stunned. Lee's hands flew
to her mouth barely in time to suppress a cry.

After a few moments Marc rolled over slowly and pushed himself painfully
to a sitting position. He looked up at Mantor who stood watching him
coldly, his fist flexing.

The comptroller licked his lips and looked around at the several men who
stood watching, their faces impassive. "Okay," he said in a
none-too-steady voice. "I'll tell you. You'd find out anyway from the
files."

"Cut the alibis and give," Mantor growled.

"Keep your shirt on." Marc's voice indicated he was regaining control of
himself. "It's H.D.T.--Hyper-Degenerate-Thorium--the stuff the
destroyers use to get extra push."

Mantor roared his glee. "Pack it aboard, boys--_all_ of it! And put it
where it will be handy, just in case."

This was it, Lee thought as she stood by, watching--the final bitter
pill. Mantor had as much as told them he was working for Venus. And the
H.D.T. was all Venus needed to be ready for war--a war that might well
blast civilization from the Solar System. Strange that so much should
depend upon one man; tragic that the one man was a weakling.

With an effort Lee forced herself to be fair. It might have done no good
to lie, she conceded. But anyone with even a normal amount of simple
courage would have tried.

It was about two hours later when the siren went off again like a
banshee wailing to a low-hanging moon. Men came running from all
directions, shouting questions at the tops of their voices.

A midget auto came skidding down the pirate ship's ramp, its driver
standing on the accelerator. The car kni