Maladjusted gang leader Cody Jarrett (James Cagney) is prone to bouts of homicidal psychosis. His unchecked delinquency is only matched by the strength of the blinding headaches and semi-epileptic seizures that incapacitate him. He's historically relied on his beloved mother Ma Jarrett to make everything better, which only highlights wife Verna's (Virginia Mayo) womanly inadequacies and inability to distract Cody from a near incestuous attachment to his mother. Cody's right-hand man Big Ed (Steve Cochran) is restless and angling for the gang's leadership while nursing designs on Cody's wife Verna. When a job goes south, Cody manages to dodge murder charges and serves time for a lesser crime. In prison, he's befriended by 'Vic Pardo'-the alias of undercover police detective Hank Fallon-and with Vic's help, he plots a seemingly perfect heist, determined to make it to the top of the world.