New episodes of "Castle" are still being produced, as of January 2016, and it stars Nathan Fillion and Stana Katic. Other cast members on the show include Susan Sullivan, Jon Huertas and Molly C. Quinn.
Nathan Fillion stars as the show's title character, Richard Castle, a successful mystery novelist who tags along on police cases for research purposes. Castle is partnered with Kate Beckett, a New York City police detective played by Stana Katic. Castle and Beckett initially butt heads, but they eventually begin to fall in love. A significant focus of the show is their developing relationship, which leads to a number of break-ups and reconciliations over the course of the series.
The show's supporting cast includes Jon Huertas as Javier Esposito, a detective who works as part of Beckett's homicide task force, and Kevin Ryan, played by Seamus Dever, another member of the task force and a good friend of Esposito. Tamala Jones plays Dr. Lanie Parish, a medical examiner and a friend of Beckett as well as the person who pushes her to act on her feelings for Castle. Recurring cast members include Molly C. Quinn as Alexis, Castle's teenage daughter, and Susan Sullivan as Martha Rodgers, a former Broadway actress and Castle's mother.