Richard Castle is a successful murder-mystery writer who discovers that a murderer is killing people in the same fashions as described in Castle's books.
The author has just killed off his main character, however it appears one of his fans liked his books a bit too much when the murders are linked back to his novels.
After questioning by police, Richard Castle joins forces with Detective Kate Beckett to solve the case. As partners, the duo begin investigating other murders in New York City.