The murder of a telephone company employee leads Mike to an underwater cable that is being tapped to access top-secret research Conferences.

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

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

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.

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

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

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

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

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

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

A group of sportsmen hire Mike to supervise their skin-diving outing, whereupon one of them sneaks off and begins photographing secret Navy facilities.

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

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

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

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

Mike discovers an important manganese deposit, but an ambitious young geologist, sharks, and an approaching hurricane threaten to silence him before he can inform the government.

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.

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

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.

Mike is hired by a playboy sportsman to supervise their underwater shark ""safari"" in the waters off Peru.

After locating a leak in a gas line and retrieving a young boy's sunken bicycle, Mike is beaten up and threatened by a gang of thugs.

An underwater camera holds the key to determining whether a woman's drowning was accidental, as her husband claims, or not.

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

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

A frustrated former athlete pushes his children to be Olympic swimmers, resulting in their becoming trapped in a cave by a rising tide.