A falsely convicted man's wife, Catherine (June Vincent), and an alcoholic composer and pianist, Martin (Dan Duryea), team up in an attempt to clear her husband of the murder of a blonde singer, Mavis Marlowe (Constance Dowling), who had been Martin's wife. Their investigation leads them to face-to-face confrontations with a determined policeman, Captain Flood (Broderick Crawford), and a shifty nightclub owner, Mr. Marko (Peter Lorre), who Catherine and Martin suspect may be the real killer.