Working for the State Department, Mike attempts to rescue a political prisoner in South America by using a harbor city's canal system.
Guest Stars:
John Zaremba, Noel Drayton
A swimsuit designer hires Mike to do an underwater fashion shoot, but corporate espionage interferes with the job.
Guest Stars:
June Blair, Maris Wrixon
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.
Guest Stars:
Byron Morrow, Michael Granger, Quinn K. Redeker
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.
Guest Stars:
Edson Stroll, Victor Buono, Nick Dimitri
Mike and a female health official try to remove a dangerously radioactive capsule from a sunken ship.
Guest Stars:
Kathie Browne
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.
Guest Stars:
Abraham Sofaer, Ric Marlow
Mike finds that someone has tapped the underwater cable used in monitoring a televised missile test.
Guest Stars:
George Eldredge
Mike rescues a diver in the Bahamas, then helps her with her research into the origin of a jade statue she owns.
Guest Stars:
Noel Drayton
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.
Guest Stars:
Bernard Kates, Bernard Fein
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.
Guest Stars:
King Moody, William Allyn
In preparation for the visit of a foreign head of state, Mike helps the Coast Guard do a security check on the area.
Guest Stars:
Myron Healey
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.
Guest Stars:
Mike Road
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.
Guest Stars:
Robert Gothie
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.
Guest Stars:
Ric Marlow
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.
Guest Stars:
Morgan Brittany
Mike searches for a vanished oceanographer by retracing her charted course.
Guest Stars:
June Blair
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.
Guest Stars:
John Archer
Mike becomes suspicious when his hired dive on a Spanish galleon yields a rare art treasure.
Guest Stars:
Joe De Santis, Al Ruscio, Barry Harvey
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.
Guest Stars:
Robert Gist
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.
Guest Stars:
Oscar Beregi Jr.
Mike helps a friend in the military with his tests of underwater radar equipment.
Guest Stars:
Russ Conway, Quinn K. Redeker
Mike straightens out a pair of teenagers who poisoned a shark Mike had captured for Marineland.
Guest Stars:
Meg Wyllie, Sal Ponti, Ken Christy
While helping to test a friend's underwater radio device, Mike discovers a submerged radio beacon, camouflaged and guarded by an electric gun.
Guest Stars:
Mike Road, Russ Conway
A small Latin American country calls upon Mike to help defuse a sunken munitions ship set to blow by saboteurs.
Guest Stars:
Leonard Nimoy
Mike goes after a newlywed teenager turned fugitive after a bungled holdup prompts him to hide in the city's storm drain system.
Guest Stars:
Beau Bridges, Tyler McVey, Anne Helm, William Boyett
Mike trains a pair of frogmen for a rescue mission in which they will rescue their kidnapped president from an ancient fortress.
Guest Stars:
Ric Marlow, Leonard Nimoy, Al Ruscio
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.
Guest Stars:
John Marley, John Qualen, Julie Sommars
The Coast Guard asks Mike to investigate the drowning death of a scientist who had invented a new type of rebreather.
Guest Stars:
Ross Elliott
A scientific society hires Mike to obtain fossil samples from a newly-discovered underwater cavern for the purpose of authentication.
Guest Stars:
Connie Hines, Maurice Dallimore
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.
Guest Stars:
William Schallert
Mike is sent by the government to investigate a jamming signal affecting a listening station in the Indian Ocean.
Guest Stars:
King Moody, Noel Drayton
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.
Guest Stars:
John Lupton, William Bakewell, Mari Blanchard
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.
Guest Stars:
John Lupton
Mike tries to outmaneuver a foreign harbormaster as he attempts to retrieve a diplomatic pouch from an airliner that crashed into the sea.
Guest Stars:
Charles Maxwell