in
searching for the jetmarine. Finally he and Arv headed back to the
submarine docks in the jeep.

A flurry of activity followed as Tom detailed ships for the search and
rounded up crews. He was interrupted by a phone call in the loading
shed. It was the control-tower operator.

"One of our drone planes has spotted a sub approaching, skipper," the
operator reported.

"What bearing?" Tom demanded excitedly.

"One-seven-six." Tom was about to hang up and grab a pair of binoculars
when the operator added hastily, "Wait! It's responding to our radio
challenge!... That's ours, all right!"

Tom dashed out of the shed and scanned the sea to the southward. Sure
enough, a jetmarine had surfaced and was speeding toward the sub docks.
Minutes later, Tom was shaking hands warmly with Zimby Cox and Mack
Avery.

"Is Bud okay?" was Zimby's first question.

"Right! I just heard from him," Tom replied. "He and Mel captured those
enemy frogmen and a copter's on the way to pick them up. What happened
to you fellows?"

Zimby confirmed Bud's guess that they had taken off in pursuit of the
enemy craft.

"We figured Bud and Mel could make out on their own," Zimby explained.
"And we thought the sub's course or actions might tip us off to its
nationality. Also, if it tried any sabotage or mine-planting, we could
radio the Navy."

Instead, Cox went on, the mysterious craft had proceeded to a point
about ten miles offshore where it rendezvoused with another submarine.

"And get this, skipper!" Mack Avery put in. "The other sub was
undetectable! We were close enough to get a peek at it, but we couldn't
ping it on the sonarscope."

"That figures," Tom said grimly. "Those frogmen were apparently
Brungarians."

Zimby Cox related that a man had transferred from the undetectable
submarine to the one they had been following. The first sub had then
headed out to sea, as if to cross the ocean back to its home base. The
other had departed on a course toward the South Atlantic.

"Probably back to the lost missile area. At least that's the way we
figured it," Zimby added.

"And neither sub spotted you?" Tom questioned.

Zimby grinned wryly. "We might not be here if they _had_ detected us.
But I'm pretty sure they didn't. Anyhow, they gave no sign."

Tom was doubly elated at the news. His antidetection gear had evidently
worked perfectly in a showdown test with the enemy, even at close range.
Moreover, if the second sub was returning