During the 1920s, a small-time Chicago criminal, Martin Snyder (James Cagney), discovers a beautiful dancer, Ruth Etting (Doris Day), after she's fired from her job at a nightclub. Under Martin's management, Ruth works her way to the top of the entertainment industry, eventually becoming a famous jazz singer and Broadway actress. But as Ruth's popularity grows, Martin's obsessive and controlling behavior begins to threaten her success and happiness.