This time it's Mike who needs rescuing when the cable attached to his Scubasphere breaks.
Mike happens upon a jealous couple prospecting for emeralds while surveying a remote river in South America.
Mike investigates when a radar jamming signal causes two sea vessels to collide with one another.
A newspaperman becomes convinced that he's dying from a fatal illness and tries to end his life in such a way that his wife can collect his insurance.
Mike must rescue a scuba diving ballerina when she catches her foot between loose plates of a sunken freighter.
Mike must retrieve a cache of medical supplies that were dumped in a river before a local witch doctor can get his hands on them.
Mike sets a charge to blow up a sunken ship that is a threat to a busy shipping lane but is unaware that a treasure hunting friend is trapped inside.
Mike is assigned to chart a path through mine-infested waters so that medical supplies can reach a port city suffering from an epidemic of cholera.
A youth to whom he's been giving diving lessons complicates Mike's efforts to retrieve a pair of radioactive cylinders.
Mike goes up against underwater heroin smugglers and uses sonar to foil their scheme.
With the help of a young Mexican boy, Mike locates a safe entrance to an underwater fossil cave.
Mike helps three women undergoing astronaut training and faces unexpected perils.
A German consulate hires Mike to salvage a survival kit from the wreckage of a World War II U-Boat.
Mike helps his former college history professor search for buried pirate treasure off the North Carolina coast.
After a man is killed testing an underwater device, Mike convinces his hesitant daughter to continue her father's work.
An man offers to pay Mike extra to continue teaching diving lessons to an inept student.
Mike and two other divers try to disarm a pair of unexploded torpedoes at the bottom of a busy harbor.
Mike's attempts to capture a poisonous lion fish are complicated by the presence of a restless youth and his girlfriend.
A test pilot must spend 24 hours in a decompression chamber after a dive in order to keep the bends from killing him.
Markings on the body of a dead diver convince a marine biologist that a killer octopus inhabits a lagoon. Mike must prove or disprove the theory.
Mike tries to make sure two salvage divers don't disappear while diving on a sunken boat off the coast of Yucatan. It seems as though a previous diver vanished completely.
Mike and an escaped Mexican convict uncover nefarious activity on an atoll off the South American coast.
Hostile natives interfere with Mike's passage downriver when he attempts to get a missionary's baby to a hospital for medical attention.
Mike goes undercover once again, this time as a tourist, in order to locate an underwater missile launcher in the Caribbean.
Mike is hired by an old Navy buddy to salvage a sunken freighter but pirates are out to make sure they get there first.
This time, Mike gets involved in couterfeiting and kidnapping when he's hired to work for the Treasury.
A woman and her father vacationing in the Bahamas become homicidal after eating a type of fish that causes hallucinations.
Mike discovers that a sunken truck is tied into the murder of a political boss and the killer is someone close to him.
After a friend of his is seriously injured in a speedboat accident, Mike goes after the movie star responsible.
Once again, Mike is somewhere in Latin America. This time he's searching a harbor for a sunken statue and discovers a homing beacon being used to guide submarines into the harbor.
An impostor posing as Mike steals diamonds from a sunken yacht but Mike is unable to provide an alibi due to the fact that he's on a top-secret mission for the government.
Mike must get insulin to a diabetic whose boat has been sunk--by his wife.
Mike once again finds himself in a full blown mess when he travels to South America. This time, his assistant is trapped underwater by an overturned truck containing drums of poison that could endanger the water supply of a port city.
A rich eccentric has invented a remote control guidance device and hires Mike to test it out, but some criminals set out to steal the device.
Someone is sabotaging a series of experiments that Mike is conducting for the Coast Guard.
Mike investigates when a hydroplane rams into a Coast Guard ship during a race.
When her father is murdered, the daughter of Mike's old Navy UDT commander gets our hero to investigate.
Mike must disarm a torpedo that's been sent into the outflow tank of a hydroelectric plant.