Brassy blonde moll Billie Dawn (Judy Holliday) hits Washington, D.C., with her unscrupulous millionaire sugar daddy, Harry Brock (Broderick Crawford), and his sleazy lawyer, Jim Devery (Howard St. John), who has been pressuring Harry to marry Billie by pointing out that a wife cannot be forced to testify against her husband. In an effort to make Billie more socially acceptable, Harry hires journalist Paul Verrall (William Holden) to smarten her up — and sparks soon fly between the pair.