Mike and Jennifer try to salvage drums of toxic waste from the ocean depths.

A man (Donnelly Rhodes) hires Mike (Ron Ely) to teach his paralyzed wife scuba diving---only to fire him when the therapy begins to show results.

When Mike (Ron Ely) is hired to study the proposed site of an underwater park, his life is threatened by men who are illegally mining the mineral-rich area.

The Nelsons investigate a marina construction company that is setting off explosions that are disturbing an underwater volcano.

A federal agent, William Taylor, hires Mike (Ron Ely) to collect evidence on a crime boss plotting a drug scam.

The Nelsons help a pearl farmer (Lisa Lau) catch the thieves who've been stealing from her each year at harvest time.

Mike confronts his worst nightmare when an old friend and an old enemy come back into his life to threaten Jenny.

When Jenny meets an acquaintance of Mike's, treasures of the sea and of the heart are in the balance, which causes Mike some measure of concern.

While scuba diving, the Nelsons discover the wreckage of a plane---which involves them in a plot to steal computer software.

A magic trick turns deadly when Mike (Ron Ely) makes the acquaintance of a temperamental illusionist who's trying to perfect his underwater escape act.

Drug smugglers force Mike at gunpoint to help them retrieve a sunken shipment of narcotics.

Jenny and Mike look into the peculiar behavior of two ecologists — and find a deadly underwater mine in the process.

When Jennifer fails to return from working on a research project in the Caribbean, Mike (Ron Ely) risks his own life to search for her.

A best-selling adventure writer lady challenges Mike to a scuba race.

Mike becomes suspicious of a woman's motives for taking diving lessons when he learns that she's afraid of deep water.

Mike becomes suspicious of a woman's motives for taking diving lessons when he learns that she's afraid of deep water.

Mike learns that the two men who chartered the Sea Hunt to go scuba diving are really seeking safety from hit men.

Two brothers (Terence Kelly, Denis Blouin) charter the Sea Hunt for a diving expedition, hoping to discover where the previous owner of the boat hid stolen treasure.

Mike (Ron Ely) is hired by a professor at the Marine Institute to search for fossils and runs up against two young thugs intent on finding the fossils before him. Kimber Sissons. Bernardo, a young Mexican boy helps Mike locate a safe entrance to an underwater fossil cave.

Mike comes to the aid of his former diving instructor, a cantankerous old man (Barney O'Sullivan) on the trail of sunken treasure.

Mike and Jennifer rescue two injured divers, who later claim to have seen a beautiful woman underwater and heard bells ringing.

The Phantom is a submarine fitted with a camera. Through the powerful underwater video camera, Mike (Ron Ely) watches two men hide something near a coral reef and his further investigations lead him to a spy ring.