Mike and Larry seek out the motive behind a doctor's sudden interest in sunken treasure. Dr. Marius J. Cattermole is an archeologist who hires divers Mike Madison and Larry Lahr to help him find a sunken Spanish galleon that supposedly rests in the Santa Barbara Channel off the Southern California coast. The expedition almost meets with disaster when a tidal wave approaches from Hawaii .

Mike Madison and Larry Lahr probe the secret of a fishing boat that sank mysteriously off the Florida coast.

Ron Ely makes his debut in the co-starring role of Mike Madison—ex-Navy diver who returns to civilian life to dive for high pay with Larry Lahr. The two salvage divers meet three people on the beach and are, soon talked into trying to recover a trophy from a sunken boat. 

Andrews and Lahr help a Slavic girl escape by sea from a false murder charge made by Slavic police. Before they're through, the pair are forced to take on another person fleeing from the police. 

The aquanauts seek the lost city of Atlantis.

Scotland Yard fails to recover valuable historical documents. Our diving herces need a safecracker to work on the ocean bottom and when they find one in prison and bring him out, the question is—can he swim? Keenan Wynn is fine as the safecracker and pretty Patricia Cutts is the brightest woman on the show so far.