American tycoon George Harrison, his beautiful wife, Mona, and deep-sea diver Jeff Clark are off the coast of Africa hoping to salvage a fortune in diamonds at the…
Far north of the Arctic Circle, a nuclear bomb test, dubbed "Operation Experiment", is conducted. Prophetically, right after the blast, physicist Thomas Nesbitt muses…
A nuclear submarine on maneuvers in the Pacific Ocean, captained by Commander Pete Mathews (Kenneth Tobey), comes into contact with a massive sonar return. The commander…
A group of scientists and their support crew of five sailors land on a remote island in the Pacific Ocean. They are searching for a previous expedition that disappeared…
In the Salton Sea, an underwater earthquake causes a crevice to open, releasing prehistoric giant mollusks. A rescue training parachute jump is conducted, but the patrol…