Castle is a Police Procedural dramedy series, created by Andrew W. Marlowe and starring Nathan Fillion and Stana Katic, which aired on ABC from 2009–16. It really can be seen as a combination of Moonlighting and Murder, She Wrote, albeit served with a generous helping of Law & Order and seasoned liberally with Nathan Fillion's natural wise-ass charm.
Fillion plays famous mystery novelist Richard Castle (an Expy of horror/suspense novelist Stephen King, according to Word of God), who begins the show having killed off his most famous main character and suffering from a severe case of writer's block.
After a killer begins to recreate murder scenes from his books, Castle is brought in to consult on the case by Detective Kate Beckett (Katic) of the NYPD. An obsessive fan is arrested, but Castle is bothered by how quickly and easily he was caught; following his writer's instincts, Castle correctly intuits that the fan was framed and helps Beckett to catch the real murderer.
Smitten by the idea of using his knowledge of criminal methodology to solve real crimes (and a bit more enamored with Beckett, who becomes the inspiration for his next main character), Castle pulls some strings and gets permission to work alongside Beckett and the NYPD as "research" for his next book. With Castle's analytical instincts (and over-active imagination) and Beckett's years of experience, they fight crime.
In 2016, ABC reported that the show would not be renewed for a ninth season, after having previously reported that Stana Katic and Tamala Jones (who played ME Lanie Parrish) were not offered their parts back if there were a ninth season.
The series finale aired on May 16, 2016.