Rocky and Dan, war buddies, are prowl car cops on night duty. Dan is a cynic who views all lawbreakers as scum; Rocky feels more lenient. Both are attracted to the radio voice of communicator Kate Mallory; but in person, Kate proves reluctant to get involved with men who just might stop a bullet. By lucky chance, Rocky and Dan cause big trouble for murderous racketeer Ritchie Garris; but when he swears vengeance, Kate's fears may prove justified.

On the eve of World War II, the German Kurt Müller, his American-born wife Sara, and their three children, having lived in Europe for years, visit Sara's wealthy mother near Washington, DC. Kurt secretly works for the anti-Nazi resistance. A visiting Romanian count, becoming aware of this, seeks to blackmail him.

The daughter of a slain man pushes her brother toward vengeance in 19th-century Corsica.

After two gang-related killings in "Center City," a suspect (who was framed) is arrested, released on bail...and murdered. Inspector Briggs of the FBI recruits a young agent, Gene Cordell, to go undercover in the shadowy Skid Row area (alias George Manly) as a potential victim of the same racket. Soon, Gene meets Alec Stiles, neurotic mastermind who's "building an organization along scientific lines." Stiles recruits Cordell, whose job becomes a lot more dangerous.

A private investigator endures the rigors of an insane asylum in order to locate $1 million in stolen loot.