Richard Castle (Fillion) is a famous mystery novelist. Bored and suffering from writer’s block, he kills off Derrick Storm, the main character in his successful book series. He is brought in by the New York Police Department for questioning regarding a copycat murder based on one of his novels, where he meets and becomes intrigued by Detective Kate Beckett (Katic), the officer assigned to the case. Castle is inspired to take Beckett as his muse for Nikki Heat, the main character of his next book series, and uses his friendship with the mayor to pressure the police to let him shadow Beckett. Castle’s exuberant personality clashes with Beckett’s more reserved and professional demeanor. However, as Beckett begins to appreciate Castle’s assistance in helping her catch killers, the two eventually become friends and then lovers. Their cases often deal with murders occurring within various unusual subcultures or milieus, including reality TV shows, vampire enthusiasts, a science-fiction convention, and a man who claims to be a time traveler. A recurring plotline deals with the unsolved murder of Beckett’s mother years before, an investigation that leads to an increasingly sprawling and dangerous conspiracy. The series also focuses on the backstories of supporting characters like Detectives Javier Esposito and Kevin Ryan, Medical Examiner Lanie Parish, Captain Roy Montgomery, and Captain Victoria Gates, through multiple episodes.
