"He must be heading for the evacuated section," said Tom.

"How do you figure that?" asked Astro, as they peered cautiously around
the edge of the doorway.

"He's wearing his oxygen mask."

"Come on!" said Astro. "Let's find out what that heel is up to."

Hugging the buildings, the two cadets walked down the street, following
Miles. There was a puzzled frown on Astro's face as he stared at the
spaceman, a hundred feet away. "I swear, Tom," he complained, "I'm about
to bust a rocket. Every time I see that guy, I think I know him, but
when I try to pin it down, it slips away from me."

"Watch it!" cried Tom. "He's stopping."

The boys ducked behind a deserted jet car as Quent Miles suddenly spun
around to stare suspiciously back down the street.

"I don't know if he saw us or not," whispered Tom.

"With that oxygen mask," replied the big cadet, "maybe he can't see very
well."

"He's going on," replied Tom. "Come on. We've got to find out what he's
up to. He wouldn't be concerned about someone following him if he
weren't trying to hide something."

They slipped around the jet car and stepped back on the sidewalk. Ahead