When psychiatrist David Manne is asked by a friend who's a New York City Police detective to consult on an unusual case, he finds himself being asked to evaluate a criminal who's the exact opposite of himself - an uneducated labourer from the Midwest who seems overwhelmed by modern day Manhattan circa 1948. But when that labourer tells David that he's not who the police say he is, David slowly begins to believe it may be true. Unable to stop himself, David begins to look into how the police handle the man, and the hospital they take him to...