"You're goin' back down?" Chow asked.

"In the seacopter," Tom replied. "To find out, if possible, who fired that projectile at us."

"Then count me in!" Chow declared, stripping off his apron. "I just hope I get my hands on them sneakin' polecats!"

Slim Davis would pilot the Sky Queen back to Shopton at once, because of Bud. Tom and Chow, meanwhile, would join Hank and his crew aboard the Sea Hound.

Ten minutes later the sleek seacopter, its searchlight off to avoid detection, was plummeting downward through water that changed before their eyes from greenish blue to a deep-gray gloom. Iridescent fish darted past the cabin window.

"Think the enemy sub was searching for our Jupiter prober?" Hank asked.

"It must have been," Tom reasoned.

Hank frowned. "Which means they must have figured out the missile's position as fast as our side did."

"And they'll play rough to stop us from finding it," Arv added forebodingly.

Within moments, the group clustered in the pilot's cabin felt a gentle bump as the Sea Hound settled on the submerged plateau. Tom relaxed at the controls but kept the rotors going so the craft would remain submerged. Meanwhile, the sonarman was probing the surrounding waters.