Johnny Eager (Robert Taylor) masquerades as a taxi driver for his gullible Probation officer, A. J. Verne (Henry O'Neill), but in reality, he is the ruthless head of a powerful gambling syndicate. Verne introduces him to socialite Lisbeth "Liz" Bard (Lana Turner), a sociology student. Johnny and Liz are attracted to each other, but then he discovers that she is the stepdaughter of his longtime nemesis, John Benson Farrell (Edward Arnold (actor)). As a crusading prosecutor, Farrell was responsible for sending Johnny to prison, and now as the district attorney, he has gotten an injunction preventing Johnny's expensive dog racing track from opening.