Korean War, April 1953. Lieutenant Clemons, leader of the King company of the United States Infantry, is ordered to recapture Pork Chop Hill, occupied by a powerful Chinese Army force, while, just seventy miles away, at nearby the village of Panmunjom, a tense cease-fire conference is celebrated.

A soldier is expected to never question the actions of his commanding officer, but when a Marine sees his CO breaking the law, he finds himself facing a difficult dilemma in this provocative war drama.

Future "first couple" Ronald Reagan and Nancy Davis made their only joint film appearance in Hellcats of the Navy. Ronnie plays Casey Abbott, commander of a WW2 submarine, while Nancy portrays navy nurse Helen Blair, Abbott's off-and-on girlfriend. During a delicate mission in which his sub is ordered to retrieve a revolutionary new Japanese mine, Abbott is forced to leave frogman Wes Barton (Harry Lauter) behind to save the rest of his crew. But Abbott's second-in-command Don Landon (Eduard Franz) is convincing that Abbott's sacrifice of Barton was due to the fact that the dead man had been amorously pursuing Helen.

Two detectives investigate the strangulation murder of a man whom everyone seemed to like.

Four astronauts returning from man's first mission to Mars enter a time warp and crash on a 26th Century Earth devastated by atomic war. At first unaware where they are, but finding the atmosphere safe to breathe, they start exploring and find themselves in a divided future where disfigured mutants living like cavemen inhabit the surface, while the normals live comfortably below the surface but are dying as a race from lack of natural water, air and sunlight.

A marine biologist and a government agent investigate mysterious deaths and rumors of a sea monster in a secluded ocean cove, and find themselves involved with a marine biology professor conducting secretive experiments, international spies trying to steal his secrets, a radioactive light on the sea bottom, and the malevolent thing which guards it.