Public Hero No. 1

Ambitious FBI agent Jeff Crane (Chester Morris) accepts an undercover assignment in a federal penitentiary. Instructed to gather information on kingpin and fellow inmate Sonny "Dinkie" Black (Joseph Calleia), Crane orchestrates a successful prison break and earns himself an invitation into Black's inner circle. As Crane moves up the ranks in Black's gang, his growing love for the ruthless gangster's straitlaced sister, Terry (Jean Arthur), further complicates an already dangerous job.