When Primus develops a sophisticated robot to complete a risky underwater operation, little does he realize that George Benton has other plans for the robot-namely to recover Russian art treasures from a sunken liner.
Nicola, a photographic model, and a woman's-lib advocate is determined to attempt a dangerous dive. Nicola steals an untested underwater breathing device that has been altered and is lethal if used.
While investigating the disappearance of all fish life off the island of Mangaya, Primus becomes involved with the kidnapping of Freemont, an American Ambassador.
An electrical storm causes an explosion and fire on an offshore oil-drilling platform. Carter Primus must rescue a colleague who is trapped in the raging inferno.
Drama involving an impending hurricane. While training dry land miners to dig on the ocean Primus discovers that two miners searching for ore samples are missing.
Toni and Charlie are trapped in a shark cage which drops to depths beyond which divers should go and Primus attempts their rescue amid a school of frenzied sharks.