The trendy elegance of director Douglas Sirk's later big-budget soap operas is nowhere to be found in Sirk's Atomic-Age melodrama Mystery Submarine. MacDonald Carey stars as Brett Young, a U.S. undercover agent whose job it is to prevent atomic secrets from falling into the wrong hands. Marta Toren co-stars as Madeline Brenner, a woman of mystery who is seemingly in cahoots with enemy agents. The film's "maguffin" consists of the top-secret info stored within the brain cells of scientist Adolph Guernitz (Ludwig Donath). The titular mystery submarine figures into the film's climax, which takes place just off the coast of Mexico.

An outlaw terrorizes the citizens of Gunsight Pass while he searches for stolen bank money that mysteriously disappeared after a robbery.

The naive Evelyn Warren, elected school teacher of the year by Time Magazine, goes to Las Vegas, where she loses a lot of money. In order to pay her debts, casino manager Matt Braddock asks her to take care of his sad little daughter Diana.

Marsha Meredith, an attorney-at-law, is nominated for a federal judgeship, but her nomination is opposed by a 'Good-Government' group that thinks her divorce makes her unfit for the job. This evolves into situations, happening in Florida, New England, Washington D.C., and the Adirondacks, such as the misunderstood husband trying to win back his wife, and the misunderstood wife trying to make her husband jealous, and one case of mistaken identity after another, after another.

Small-town gossips rage over the arrival of a mysterious stranger.

Joseph Cotten plays an assistant bank manager who steals $1,000,000 from the safe late on a Friday and then plans to flee to Brazil over the weekend.