The "ex" of the title is daffy mystery-writer Jean Arthur, former wife of urbane doctor William Powell. When Powell becomes the prime suspect in a murder case, Arthur endeavors to solve the case herself -- and to reclaim her ex-hubby in the process. After a well-directed semiclimax at a race track, the killer is revealed during one of those expository scenes in which all the suspects are gathered together in one room. The murderer attempts to escape, and Powell is knocked cold in the process. When he awakens, he discovers that Arthur has set up some projection equipment, and is running a film of a minister reciting the wedding vows. Curses! Trapped again! Like William Powell's previous RKO effort Star of Midnight, The Ex-Mrs. Bradford was an attempt to cash in on the popularity of Powell's Thin Man films.