Kansas City Confidential tells the tale of Timothy Foster, a corrupt ex-policeman who, in blackmailing three criminals to complete a robbery, incidentally implicates a man unrelated to his scheme but gets mistaken for Foster by the authorities. The man, Joe Rolfe, eventually gets the charges against him dropped but goes to track down Foster and the original criminals in a fit of anger. What happens thereafter incites the curiosity lead on by the text on the poster, which reads: "The true solution to this shocking crime still hasn't been entered on police records!!". Actors John Payne and Coleen Gray are listed as the stars of the film and are featured in the lower right-hand corner of the poster. A photomontage of guns and physical altercations complete the rest of the poster, indicating the violence in the film. Kansas City Confidential is significant in film history as one of the most violent crime films of its time.