When the NYPD begin questioning Richard Castle (Nathan Fillion), a famous mystery novelist and divorced father raising a teenage daughter (Molly Quinn) with the help of his Broadway diva mother (Susan Sullivan), about a case involving a series of murders staged to imitate crime scenes from his books, Castle finds inspiration in Detective Kate Beckett (Stana Katic), a bright and aggressive homicide cop with a fascination for odd and offbeat cases. Though they instantly clashed, sparks of another sort began to fly, leading both to danger and a hint of romance as Castle stepped in to help find the copycat killer. He abandons his successful Derrick Storm book series, and appoints himself as a consultant helping the police solve New York’s toughest murder mysteries. He’s found a new muse, and she’s the inspiration for his new character, Nikki Heat. Eventually, Castle learns that Beckett’s mother was killed when she was younger, and helps her begin to solve the years-old unsolved murder.