Ex-Navy Underwater Demolition Team Officer Mike Nelson continues his skin-diving as a postwar profession...combining mastery of the scuba and spear with a flair for dangerous investigation.
Cinematographer: Lamar Boren
Producer: Ivan Tors
Producer: Frederick Ziv
Strong Box: 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.
The Fearmakers: In preparation for the visit of a foreign head of state, Mike helps the Coast Guard do a security check on the area.
Revolutionary Spoils: 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.
Pirate Gold: 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.
The Living Fossil: 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.
Submarine Explosion: Scientists risk triggering a tidal wave when they ignore Mike's warnings about the strength of the explosive charges they're using.
Sacred Pool: 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.
Cindy: 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.
Cross Current: Mike searches for a vanished oceanographer by retracing her charted course.
Synthetic Hero: 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.
The Cellini Vase: Mike becomes suspicious when his hired dive on a Spanish galleon yields a rare art treasure.
Target: 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.
Ghost Lite: An East Indian oceanographer vanishes during a series of underwater experiments with infra-red light.
Rebreather: 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.
Blind Spot: Mike helps a friend in the military with his tests of underwater radar equipment.
The Replacement: Mike straightens out a pair of teenagers who poisoned a shark Mike had captured for Marineland.
Underwater Beacon: While helping to test a friend's underwater radio device, Mike discovers a submerged radio beacon, camouflaged and guarded by an electric gun.
Time Fuse: A small Latin American country calls upon Mike to help defuse a sunken munitions ship set to blow by saboteurs.
Storm Drain: Mike goes after a newlywed teenager turned fugitive after a bungled holdup prompts him to hide in the city's storm drain system.
The Invader: Mike trains a pair of frogmen for a rescue mission in which they will rescue their kidnapped president from an ancient fortress.
Changing Patterns: 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 Catalyst: The Coast Guard asks Mike to investigate the drowning death of a scientist who had invented a new type of rebreather.
The Missing Link: A scientific society hires Mike to obtain fossil samples from a newly-discovered underwater cavern for the purpose of authentication.
Underwater Narcotics: 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.
The Sound Of Nothing: Mike is sent by the government to investigate a jamming signal affecting a listening station in the Indian Ocean.
Prima Donna: 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.
Beyond Limits: 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.
Diplomatic Pouch: Mike tries to outmaneuver a foreign harbormaster as he attempts to retrieve a diplomatic pouch from an airliner that crashed into the sea.
Man Overboard: Mike responds to a "man overboard" situation, but an extensive search turns up no victim.
Point Of No Return: Mike is trapped in a "scubasphere" when the cable attached to it snaps.
River Treasure: 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.
The Destroyers: Mike investigates the source of a radar jamming signal that caused two ships to collide.
Vital Error: 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.
The Dancer: A scuba diving ballerina faces the possibility of underwater amputation when she catches her foot between the buckled plates of a sunken freighter.
Sperling Of Lamatsue: 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.
Rescue: 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.
Mercy Strip: Mike scouts a path through mine-infested waters so that medical supplies can reach a China Sea port hit by a cholera epidemic.
Hot Tracer: 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.
Sonar Story: Mike uses sonar to foil a gang of underwater heroin smugglers.
Amigo: A young Mexican boy helps Mike locate a safe entrance to an underwater fossil cave.
The Aquanettes: Mike faces sharks and other unexpected difficulties while working with three pretty women undergoing astronaut training.
Survival Kit: Mike is hired by a local German consul to salvage a survival kit from the wreckage of a Nazi warplane in the Caribbean.
Expedition: 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.
Bionics: Mike convinces a reluctant daughter to continue her father's work after he is killed testing an underwater electrical detection device.
The Defector: A man bribes Mike to continue giving lessons to an inept diving student whom he's stopped teaching.
Magnetic Mine: Gathering museum specimens in the coastal waters off lower California, Mike Nelson learns of a derelict mine which has drifted into the harbor of a nearby town. The town's principal industry - a nitrate factory - will blow up and destroy the city if the mine explodes. Mike works with local fishermen to locate the drifting "killer" before it costs hundreds of lives.
Explosion: "Killer Rock," a jagged, treacherous, underwater off-shore peak, tears the hulls of passing ships like paper. Mike Nelson's assignment: destory it! Mike, armed with dangerously unstable explosives, fights ocean currents and an attack by an electric ray to fulfill his job.
The Amphibian: Six sportsmen rent an amphibian plane to fly them to a good skindiving site. Mike Nelson is hired to supervise their safety. When one of the divers, using a Sea Scooter, mysteriously disappears, Mike searches and finds him - photographing secret Navy installations! Mike Nelson, armed only with a dagger, cometes for his life against the spy's powerful spear-gun.
Lord Christobal: The Caribe Insurance Company sends Mike to the West Indies to investigate the sinking of a freighter. On arrival, Mike finds a shipping executive murdered, a grim warning someone doesn't want Mike to investigate! A Calypso singer helps Mike solve the murder and the mystery of the sunken ship.
Decoy: Two Mexican fisherman show Mike a net with an odd hole in it and claim an unknown species of sea monster caused it. Mike Nelson, using whale-tracking equipment and underwater microphones, risks his life to track and trap the 'monster.'