The Castle After Show recaps, reviews and discusses episodes of ABC's Castle. Show Summary: Castle is an American crime drama television series, which premiered on ABC on March 9, 2009. The series primarily traces the lives of Richard Castle, a best-selling mystery novelist, and Kate Beckett, an NYPD homicide detective, as they solve various unusual crimes in New York City. Detective Beckett is initially infuriated at the thought of working with a writer and goes to great lengths to keep him out of her way. However, the two soon start developing feelings for each other. The overarching plot of the series focuses on the romance between the two lead characters, and the murder of Beckett's mother.