Through a powerful underwater video camera, Mike watches two men hide something near a coral reef and his further investigations lead him to a spy ring.

A pair of drug smugglers take Jennifer hostage and force Mike to retrieve a cocaine package from the ocean floor.

Mike Nelson matches wits with two desperate culprits who know secrets about his boat.

Mike is caught in a web of intrigue when two plausible strangers hire the Sea Hunt to hide from contract killers.

Jenny uses state-of-the-art science to outwit a clever crook who plans murder to hide a million-dollar swindle.

Mike Nelson and his daughter decide to find out about a mysterious legend about a mermaid who haunts the sailors of a fishing village. Fiction becomes reality when Eric, a fisherman, spots a strange being.

Mike has an underwater reunion with the man who taught him to dive, a man with a secret obsession.

A fragile marine fossil bed is at risk when Mike fights deadly current to combat destructive intruders.

Mike is mystified when a pretty young diving student insists on learning to dive despite her obvious fear of deep water.

Mike is challenged to an underwater race by a glamorous writer who means to win by fair means or foul.

Mike uses hi-tech magic of his own when Jennifer's friend Verna almost drowns in an underwater escape act.

Mike returns from a salvage job to be told that the Sea Hunt has been found adrift, but that Jenny is lost at sea.

Mike and Jenny find a deadly underwater minefield when they investigate the odd behavior of two inconsistent ecologists.

Discovery of an underwater plane wreck puts Mike and Jenny in jeopardy as a white collar crime turns murderous.

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.

Mike confronts his worst nightmare when an old friend and an old enemy come back into his life to threaten Jenny. Mike is happy to see his old friend Jason Stallworth again after many years but becomes suspicious when Mike catches him talking with a dangerous criminal. 

Mike and Jenny come to the assistance of Yasuko Tamuri, a pearl bed owner lady whose pearls are mysteriously disappearing.

A Federal agent hires Mike to gather evidence on a crime boss who's planning a drug scam.

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

When Mike 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.

A man hires Mike to teach his paralyzed wife scuba diving---only to fire him when the therapy begins to show results.

The Harbor Patrol asks the Nelsons to retrieve two drums containing toxic waste from the ocean.