When Castle’s idol, a famously reclusive author, turns up dead, Castle is determined to solve his hero’s murder. But as he and Beckett dig deeper, they discover that truth is stranger than fiction.
Castle is captured and forced to work with strangers to solve deranged puzzles and mind games, while Beckett and the 12th Precinct must race against time to rescue Castle and catch a killer.
When the body of a local college fraternity student is found gruesomely murdered, Castle has to go undercover as a professor in order to gain access to the victim's world. However, he and Beckett soon discover that behind the fun and games of college are some darker secrets the university wants to keep hidden.
When the son of a Russian diplomat turns up murdered, Beckett and Castle find themselves in a dangerous game of international crime and punishment, with Castle having to entertain a jovial Russian security officer who winds up more involved than anyone planned.
Beckett receives a mysterious tip and is launched into a fight for her life with mercenaries on her tale; Castle tries to determine why his wife is on the run.
When a movie star turn stage actor is mysteriously killed, Castle and Beckett go backstage and discover he had more than his lines to worry about.
Castle goes to Los Angeles in hopes of finding answers about the time he can't remember, but ends up in danger when he is recruited by the Greatest Detective Society.
Castle and Beckett investigate the murder of a cruise ship entertainer, only to find themselves trapped at sea with the killer.
The murder of a man connected to smuggling Turkish relics sends Castle, Beckett and the 12th Precinct on a search for a stolen antique believed to be Aladdin’s lamp, in hopes that it can lead them to the killer.
When a recruit officer at the NYPD Academy is killed, Beckett and the team go back to their old training ground to investigate. Meanwhile, Castle must reckon with a decision with profound consequences for him and Beckett.