As part of a research project, Mike Nelson attempts to spend three days underwater at a depth of 250 feet in a pressure chamber dubbed Scubasphere. A tropical storm pops up, and both the cable and telephone connections attached to the Coast Guard ship above are severed. To make matters worse, the ship heads for safer waters without realizing that Mike has lost his connection to them. Written by jimmie d

While in a South American jungle, Mike tangles with a jealous treasure hunter.

Mike investigates the mysterious collision of two Navy destroyers.

Mike's normally level-headed skindiving buddy begins to exhibit peculiar behavior.

Mike desperately tries to save the life and limb of a popular dancer whose leg is hopelessly pinned in wreckage 90 feet below the surface.

Mike tries to recover valuable medical supplies that an Asiatic warlord has dumped into the river.

Mike must dive to rescue a friend trapped in a sunken wreck, with just minutes left until explosive charges are set to blow it to pieces.

Mike risks his life in order to sneak badly needed medical supplies through a dictator's mine-infested blockade.

Problems arise as Mike attempts to retrieve a pair of radioactive cylinders leaking dangerous amounts of radiation underwater.

Using sonar equipment on his boat, Mike tracks heroin smugglers.

Mike travels to Mexico in search of underwater fossils in an inaccessible cave.

Mike takes part in a special program known as Operation Astronette. His job is to train three female astronauts in underwater survival skills.

Mike attempts to salvage a survival kit from a German fighter plane shot down during World War II.

Professor Halliday wants more money to carry on his underwater exploration.

An inventor dies while testing a new underwater detection device.

Mike tells an inept skin-diving pupil that there's no point in continuing his lessons.

Mike attempts to diffuse two sunken torpedoes, as well as diffusing the racial tensions between the Japanese and American members of his 3-man team.

Mike and a young man, whom he had helped rehabilitate when he was a juvenile delinquent, fly to Hawaii to hunt for lionfish, one of the most venomous fish on the ocean floor.

Mike and his partner fight the bends, as they endure a long recovery process in a submarine's escape trunk.

Mike and his diving team are attacked by a violent new breed of octopus.

While searching for a sunken wreck, Mike's hard hat diving partner disappears, leaving nothing behind but his torn air hose attached to their boat on the surface.

While on a covert mission for the U.S. Government, Mike discovers a few unsavory inhabitants on what was supposedly a deserted island.

While in the dangerous jungles of Ecuador, Mike takes desperate measures to save the life of his very ill infant godson.

Mike travels undercover to the Caribbean Coast on a secret mission for the United States Government.

It's a battle of wits, as Mike tries to outsmart pirates intent on hijacking the cargo of a sunken wreck that he found.

Mike is recruited to track down counterfeiters.

While Mike is in Nassau on a salvage job, two of his friends catch and eat a strangely poisonous fish for breakfast, which causes severe hallucinations that trigger suicidal and homicidal tendencies.

After being falsely arrested for diving in a bay, Mike sets out to solve a murder mystery.

A female diving friend of Mike's is hospitalized with severe injuries sustained by a hit-and-run speedboat piloted by a popular movie star.

Mike is recruited to rescue the statue of a Saint who falls off a ship into the sea. The locals believe this is the cause of many problems in the area including the poor fishing.

Mike is suspected of insurance fraud, after an impostor steals a valuable necklace.

Mike is invited to join a longtime friend and her workaholic husband on their expedition to explore an Aztec ceremonial pool on an uninhabited island located 15 miles off the coast of Mexico. Mike's friend unwittingly puts her husband's life in jeopardy, when she deliberately strands the trio on the island. Written by jimmie d

A South American city's water supply is threatened by a drum of poison from an overturned truck.

While vacationing in Nassau, Bahamas, Mike meets an eccentric multi-millionaire inventor and his sister. He helps the man experiment with an underwater remote control device used to guide boats.

Mike battles underwater saboteurs, as he assists the US Navy with underwater sound travel experiments.

Mike investigates the ramming of a Coast Guard boat by a hydroplane piloted by a friend of his during a race.

Mike Nelson sets out to prove that the death at sea of a friend's father was the result of murder.

Underwater explosives threaten to make this Mike Nelson's final dive.