Mike tries to free the pilot of a downed jet from his watertight cockpit before his air runs out, without causing the man's death from the water pressure.

While investigating the cause of a mine flood that killed thirty men, Mike stumbles upon an air pocket with two survivors.

A grudge between two divers whom Mike is testing for underwater mining skills becomes a secondary issue when one of them contracts nitrogen narcosis.

Before Mike can investigate the disappearance of a pair of skin-diving geologists, one turns up dead on the beach bearing marks resembling the suction valves of a giant octopus.

Mike helps the Immigration Department Border Patrol break up an underwater border-running operation.

A beautiful woman hires Mike to give her diving lessons for mysterious reasons.

An attractive magazine photographer hires Mike to assist her in getting pictures of a sunken barge off the coast of Mexico.

Hired to test a new electronic fish-finder, Mike encounters a village where every fish in the vicinity has disappeared.

A pair of ruthless treasure hunters dupes a young skin diver into helping them loot a sunken ship.

Mike dives into the Caribbean to recover the lost nose cone from an ICBM rocket before enemy agents can get it.

A killer whale is capsizing boats and endangering scuba divers and swimmers along a stretch of coastline.

Mike plays commando in rescuing a scientist who had defected from Soviet kidnappers who are returning him to Moscow aboard a Pacific liner.

Mike and two cameramen are imperiled when an irrationally jealous man drops their camera cage into shark-infested waters.

Mike competes with a pair of helmet divers to salvage a German submarine sunk off the coast of South America.

A man claims to have invented a machine that can locate ships carrying gold.

Mike is nearly killed by a massive electrical jolt used by a poacher to kill fish in the Florida Everglades.

Mike comes to the aid of a female escape artist when her underwater stunt goes awry.

Mike interrupts an underwater survey in the Gulf of Mexico in order to save a diver whose air line has become snarled.

Mike supervises a diamond diving expedition in South America, but discovers that his employers are poaching on someone else's property.

A vicious alligator escapes from a wild animal show and takes refuge in the lake of a public park.

An entire Mexican town is menaced by the presence of a derelict floating mine in its harbor that could ignite fumes from the local nitrate factory if it is detonated.

The State of Florida hires Mike to organize and train an underwater police force to deal with a series of underwater crimes.

Mike investigates an underwater grotto said to feature a mermaid that lures men to their deaths.

A professor and his daughter hire Mike to help them search for a rare underwater plant in Costa Rica.

A pair of prospectors hire Mike to trace the source of radioactive fish with a Geiger counter in hopes of finding a uranium deposit.