Mike must find and disarm a torpedo that's been sent into the outflow tube of a hydro-electric plant.
Mike helps the daughter of his old UDT Commander investigate the man's death, which she believes was murder.
During hydroplane races, a friend of Mike's rams his craft into a Coast Guard ship, leaving Mike to investigate.
A naval officer of a Caribbean nation is sabotaging a series of experiments Mike is conducting with the Coast Guard.
Mike helps test a remote control guidance device invented by a rich eccentric.
Mike's assistant is trapped underwater by an overturned truck containing drums of poison that could endanger a South American city's water supply.
While on a diving expedition in Guatemala, a woman seeking to slow down her husband's frantic lifestyle deliberately sinks the boat they share, unaware that her husband is a diabetic and his insulin supply will be lost with the vessel.
A dead ringer for Mike is stealing diamonds from a sunken sports cruiser, but when Mike is accused of the crime, he is unable to establish an alibi due to his current top-secret mission.
While searching a Latin American harbor for a sunken statue, Mike discovers a UHF homing beacon being used to guide submarines into the port.
Mike goes after an egocentric movie star who injured a friend of Mike's in a hit-and-fun speedboat accident.
A sunken truck points Mike to the murder of a political boss, and the killer is the father of a good friend of Mike's.
A pretty woman and her father, vacationing in the Bahamas, become killers after inadvertently eating a variety of fish that causes hallucinations.
While working for the U.S. Treasury to break a counterfeiting ring, Mike intercedes in a kidnapping.
Pirates try to snatch a sunken freighter away from Mike before he can salvage it for an old Navy buddy.
Mike poses as a tourist on vacation as he tries to locate a hidden underwater missile launcher in the Caribbean.
Mike must get past Jivaro Indians who are blocking his passage downriver as he attempts to get a young missionary's baby to a hospital for medical attention.
Mike teams up with a Mexican prison escapee to uncover nefarious activity on an uncharted Pacific atoll off the coast of South America.
One salvage diver disappears while diving on a sunken yacht off the coast of Yucatan, and Mike tries to see that two others don't share his fate.
Markings on the body of a dead diver convince a marine biologist that a tropical lagoon is inhabited by a killer octopus.
A heroic test pilot from the Korean War has his mettle tested when he must spend 24 hours with Mike in a makeshift decompression chamber after a dive to prevent the bends from killing him.
A restless youth and a college girl complicate Mike's attempts at capturing a poisonous lionfish.
Mike heads a three-man team in an effort to disarm a pair of unexploded torpedoes at the bototm of a West Coast harbor.
A man bribes Mike to continue giving lessons to an inept diving student whom he's stopped teaching.
Mike convinces a reluctant daughter to continue her father's work after he is killed testing an underwater electrical detection device.
While helping his former history professor search for pirate treasure off the North Carolina coast, Mike finds evidence that the underwater cave said to house the treasure has been tampered with.
Mike is hired by a local German consul to salvage a survival kit from the wreckage of a Nazi warplane in the Caribbean.
Mike faces sharks and other unexpected difficulties while working with three pretty women undergoing astronaut training.
A young Mexican boy helps Mike locate a safe entrance to an underwater fossil cave.
Mike uses sonar to foil a gang of underwater heroin smugglers.
Mike's efforts to retrieve a pair of radioactive cylinders are complicated by the presence of a headstrong youth to whom he's been giving diving lessons.
Mike scouts a path through mine-infested waters so that medical supplies can reach a China Sea port hit by a cholera epidemic.
Unaware that two of his treasure-hunting friends are trapped inside, Mike sets charges to blow up a sunken ship that is a menace to a busy shipping lane.
After being accidentally caught in a fishing net, Mike challenges an Asiatic warlord by trying to retrieve a cache of medical supplies that the dictator has dumped into a river.
A scuba diving ballerina faces the possibility of underwater amputation when she catches her foot between the buckled plates of a sunken freighter.
A famous newsman, convinced that he has a fatal illness, tries to end his life in such a way that his wife can collect his insurance, with Mike as a witness.
Mike investigates the source of a radar jamming signal that caused two ships to collide.
While surveying a remote river in the South American jungle, Mike is threatened by the jealousy of a man prospecting for emeralds with his wife.
Mike is trapped in a ""scubasphere"" when the cable attached to it snaps.
