would be a telltale sign should anyone notice it.

She crept toward the adjoining main room from whence came the low
murmur of voices. Secreting herself behind a tall pile of old sawed
boards, she peered through the doorway.

The truck had pulled up at one side of the room. Several rough looking
men were engaged in unloading the wheels. Penny's eyes fastened upon
the man who directed the others. It was Rap Molberg.

"Get a move on!" he ordered tersely. "We can't stall around all night."

The wheels were trundled out one by one from the rear end of the truck,
and the men, six in all, fell to work with their tools, defacing the
serial numbers and substituting others. Penny watched in fascination.

Her gaze wandered to Jerry Barrows who had driven the truck to the
sawmill. He sat apart, apparently taking no interest in what was going
on.

Somewhere in the building a telephone rang. As one of the men came
toward her, Penny shrank down behind the pile of lumber. He passed so
close that she could have reached out and touched him had she chosen.

The man went into a small anteroom and Penny heard him answer the
telephone. She could not distinguish the words, but presently he
returned to the main room.

"It was the big boss," he reported to Rap Molberg. "He called from
Somm Center."

"What's he doing there?" Rap demanded irritably. "Doesn't he think I'm
capable of handling this end?"

"He's on his way here now," the other informed. "He says he has a hot
tip that Christopher Nichols is wise to our hideout!"

"That snooper!" Molberg snarled. "I should have known he was up to
something when he left town so suddenly."

"The cops may be down on us any minute."

"Then we're getting out of here without leaving any evidence behind!"
Molberg snapped. "Get busy, men!"

All fell to work with a will save Jerry Barrows.

"You!" Rap shouted angrily. "This is no time for loafing!"

"I agreed to drive a truck, but I didn't say I'd deface tires and help
with your thieving!" the boy retorted bitterly. "I'm sick and tired of
the whole deal."

"Oh, so you're sick and tired of it, are you?" the other echoed
sarcastically. "You're in this the same as the rest of us, and if we
go to the pen, you go with us! Now get to work or I'll----"

He left the threat unsaid, for just then an automobile engine was heard
outside the building. Everyone froze in an attitude of listening.
Molberg dropped his tools and ran t