The plot was growing thicker.

And it was suffocating under that heavy robe, now that there was no free air blowing about it.
"Where's the stuff ?" one of the men asked.
"On the back seat," said the other.
Pee-wee trembled.
"Oh, no, I guess it's on the floor," the man added, "I think I put the silver cup under the back seat--" Pee-wee shuddered.

So they had been stealing silver cups.
"Either there or--oh, here it is." Pee-wee breathed again.
Then he heard no more voices.

But he heard other sounds.

He heard the creaking of a heavy rolling door.