After taking over as deputy of the Bureau of Weights and Measures, boxer Johnny Cave (James Cagney) finds himself up to his neck in corruption. At the root of the problem is city alderman Marty Cavanaugh (Robert Gleckler). When Cave tries to bring Cavanaugh down, he becomes the victim of a frame-up. With trouble lurking around every corner, Cave and his fiancée (Mae Clarke) must clear his name and stop Cavanaugh's thugs in this gritty classic.