Wildly famous mystery novelist Richard Castle (Nathan Fillion), who is bored with his own success, learns that a real-world copycat killer has started staging murder scenes depicted in his novels. Rick is soon questioned by NYPD Detective Kate Beckett (Stana Katic), a very bright, aggressive detective who keeps her investigations under tight rein. Rick and Kate's styles instantly clash, yet sparks begin to fly, leading both to danger and a hint of romance as Castle steps in to help find the killer. And once that case is solved, he and Beckett build upon their new relationship as they look to solve strange homicides in New York - as much fun as one can have with death & murder. Castle is kept grounded by his Broadway diva mother, Martha Rodgers (Susan Sullivan) and quick-witted teenage daughter Alexis (Molly Quinn).