Plot

John Skillpa, a quiet bank clerk living in tiny Peacock, Nebraska, prefers to live an invisible life in order to hide his secret: He has multiple personality disorder, the implied result of childhood trauma inflicted by his abusive mother. His alter ego is a woman, Emma, who each morning does his chores and cooks him breakfast before he starts the day. Then, in a moment, everything changes. A freight train caboose runs off its tracks and crashes into John's backyard, destroying his wood fence. When neighbors descend on the scene, they discover Emma for the first time and mistakenly believe her to be John's wife. This launches John into the glare of the spotlight, threatening to reveal his secret life. He must then fool the town into believing he and his alter ego are man and wife. A young, struggling single mother, Maggie, holds the key to his past and sparks a battle between the personalities. Now John must try to stop Emma from taking over completely.

Cast

* Cillian Murphy as John Skillpa, a "retiring, shy and completely nondescript bank employee" leading a double life as Emma, his female alter ego. Murphy states that "Peacock stunned me as a script from start to finish. It offers an incredible challenge to an actor — one I couldn't turn down."
* Ellen Page as Maggie, a struggling young mother who holds the key to John's past and sparks a battle between the personalities. Page comments, "This is one of the boldest screenplays I've come across in my albeit short career; it's a character and story I can throw myself into and exactly the type of movie I love to be a part of."
* Susan Sarandon as Fanny Crill, the wife of Peacock's mayor, who also runs a local woman's shelter. Sarandon has said that Peacock is "a very strange little piece — kind of ominous."
* Bill Pullman as Edmund French, John's boss. Pullman has described Peacock as "a very interesting script," explaining that his role "is another character hiding the fact he's the closest one like [Skillpa]. It's a very different part for me."
* Josh Lucas as Tom McGonigle, a local police officer and the closest thing John has to a friend.
* Keith Carradine as Mayor Ray Crill
* Paul Cram as Kenny, a local store clerk.