The movie starts with showing Catherine (Cat) Ballou (Jane Fonda) in a jail cell awaiting hanging. Her story is told by wandering musicians (Stubby Kay and Nat King Kole). On the train on the way home from boarding school, where she was going to learn to be a schoolteacher, she meets a criminal (Michael Callan) and his uncle. When she gets home, she learns her father has been threatened if he doesn't sell his ranch. She decides to hire a gunslinger that she has been reading stories about, Kid Sheleen (Lee Marvin). He shows up, but is nothing like his comic book persona. He is a drunk, but she keeps him around. After her father's murder, she is determined to avenge it by finding out who killed him. She and her gang have some wild adventures while trying to discover the killer. The high point of the movie is Kid Sheleen's plan for her father's killer and her attempted rescue from the hangman.