Working for the State Department, Mike attempts to rescue a political prisoner in South America by using a harbor city's canal system.

A swimsuit designer hires Mike to do an underwater fashion shoot, but corporate espionage interferes with the job.

Mike attempts to deal a blow to organized crime by using a periscope camera to photograph a secret meeting of mob bosses at a lakeside estate.

Mike finds high radiation coming from the hull of a foreign freighter, but when the Coast Guard investigates, they find no trace of the radioactivity.

An accidental death puts Mike onto an espionage ring that is using an underwater cave for a microfilm drop site.

Mike, working with a pretty Secret Service agent, poses as a scientist in order to retrieve a cache of counterfeit currency from a crashed Nazi plane off the coast of a Caribbean republic.

Mike finds that someone has tapped the underwater cable used in monitoring a televised missile test.

Mike rescues a diver in the Bahamas, then helps her with her research into the origin of a jade statue she owns.

While on patrol with the Coast Guard Auxiliary, Mike discovers a deported crime boss trying to re-enter the country, then has to rescue him from some old enemies.

Mike leads the way in a salvage operation to recover more than a million dollars' worth of gems from the captain's safe of a sunken ship.

In preparation for the visit of a foreign head of state, Mike helps the Coast Guard do a security check on the area.

A new revolutionary leader asks Mike to help him retrieve his country's hidden gold reserves, believed to have been hidden aboard a scuttled freighter by the ousted former dictator.

While marking underwater sites for demolition by a construction company, Mike learns that a young boy is trapped in a submerged grotto that has already been mined with an explosive.

While supervising an expedition in the Indian Ocean to find a rare coelacanth fish, Mike finds that the organizer is dangerously eager to impress his fiance.

Scientists risk triggering a tidal wave when they ignore Mike's warnings about the strength of the explosive charges they're using.

Mike faces arrows and an alligator in the Mayan jungle while searching for a drug that could be a boon to medicine or a dangerous narcotic.

Mike tries to reach a little girl trapped in the air shaft of a mine located at the edge of a man-made lake, but the potential for a landslide hampers his attempt.

Mike searches for a vanished oceanographer by retracing her charted course.

Mike discovers the wreck of a navy ship that disappeared mysteriously, and is joined by a pair of its former crew members when he dives to examine it.

Mike becomes suspicious when his hired dive on a Spanish galleon yields a rare art treasure.

While diving in Lake Ontario, Mike is sent by the Coast Guard to investigate an item that crashed into the lake nearby, which may be an enemy ICBM.

An East Indian oceanographer vanishes during a series of underwater experiments with infra-red light.

Mike and an old war buddy use a new, untested ""re-breather"" to investigate an underwater missile site being constructed in the channel of a privately-owned island.

Mike helps a friend in the military with his tests of underwater radar equipment.

Mike straightens out a pair of teenagers who poisoned a shark Mike had captured for Marineland.

While helping to test a friend's underwater radio device, Mike discovers a submerged radio beacon, camouflaged and guarded by an electric gun.

A small Latin American country calls upon Mike to help defuse a sunken munitions ship set to blow by saboteurs.

Mike goes after a newlywed teenager turned fugitive after a bungled holdup prompts him to hide in the city's storm drain system.

Mike trains a pair of frogmen for a rescue mission in which they will rescue their kidnapped president from an ancient fortress.

When Mike is called upon to teach scuba diving to his former mentor who trained him in helmet diving, he finds that the older man is not physically up to it.

The Coast Guard asks Mike to investigate the drowning death of a scientist who had invented a new type of rebreather.

A scientific society hires Mike to obtain fossil samples from a newly-discovered underwater cavern for the purpose of authentication.

Mike discovers a plant growing profusely on the ocean floor that turns out to be a hybrid cannabis, and he is speared when he investigates further.

Mike is sent by the government to investigate a jamming signal affecting a listening station in the Indian Ocean.

Another movie company using Mike as an advisor needs his help when a planned torpedo blast traps the star and a Hollywood columnist onboard a sinking ship.

Mike races foreign agents to a missile fired from Central Asia in order to photograph it on the sea bottom and obtain its data recorder.

Mike tries to outmaneuver a foreign harbormaster as he attempts to retrieve a diplomatic pouch from an airliner that crashed into the sea.

Mike responds to a ""man overboard"" situation, but an extensive search turns up no victim.