Castle & Beckett confront the possibility of paranormal foul play when a world renown ghost hunter is mysteriously murdered while investigating a haunting at a legendary New York mansion.
During the investigation of the murder of an Atlantic City casino owner at an abandoned warehouse, strong leads emerge for the team in both New York and Atlantic City. As Beckett and Capt. Gates work the New York leads together, Castle naturally chooses to join the detectives for the road trip to "America's Playground," hoping to help solve the case while throwing an impromptu bachelor party for Ryan.
When a lothario is killed, Castle and Beckett suspect that the victim’s mysterious double life holds the key to his murder. Their investigation leads to a shocking twist that threatens to disrupt Ryan’s wedding with Jenny.
In the first episode of a two-part "Castle" event, Castle and Beckett pursue a ruthless killer who, they discover, is part of a sinister, international conspiracy. Castle and Beckett are joined on the case by Sophia Conrad (guest star Jennifer Beals, "The Chicago Code," "Flashdance"), a smart, sexy CIA operative who has a complicated past with Castle. Josh Stamberg, ("Drop Dead Diva") also guest stars as Martin Danberg, an intelligence officer.
When a famous dog trainer is killed, the investigation keeps coming back to charismatic reality TV star Kay Cappuccio (guest star Hilarie Burton, "White Collar"). Kay, a favorite of tabloids and gossip websites the world over, has achieved stardom without possessing any discernible skill or talent. But there seems to be more to her story than she is letting on.
A devilishly handsome detective from Scotland Yard, Simon Hunt (Brett Tucker, "Off the Map," "Spartacus," guest stars), teams up with Castle & Beckett to find the person responsible for the murder of his friend's daughter. Also, Charles Shaughnessy ("Days of Our Lives") plays Nigel Winthrop, the Deputy General at the British Consulate whom Castle & Beckett suspect is up to more than just ambassadorial balls and diplomatic luncheons. Meanwhile, Lanie convinces Beckett that she needs to make a move on Castle before it is too late.
When a woman dressed as Red Riding Hood is found dead in the woods with claw marks covering her body, and soon after a murdered Snow White is discovered with a poison apple in her hand, Castle & Beckett find themselves on a Grimm hunt to catch a fairytale killer before he kills again. But nothing is as it seems in a case filled with deceit, betrayal, secrets and murder.
When a bomb explodes at a protest rally killing five people, Castle & Beckett realize the key to solving the case is to reconstruct the 47 seconds prior to the explosion. Using video and witness accounts, they uncover the shocking truth about who planted the bomb.
With tensions rising between Castle and Beckett, Castle finds himself a new partner -- Detective Ethan Slaughter (guest star Adam Baldwin, "Firefly"), a tough and colorful cop from the city's gang unit. But Castle gets more than he bargained for when Slaughter shows him a grittier side of police work that puts Castle in the line of fire like never before.
Derek Webster (“Desperate Housewives,” “Damages”) guest stars as Mayor Robert Weldon, Castle’s longtime friend and the Mayor of New York City. It was Mayor Weldon’s political clout that allowed Castle to partner up with Beckett. But now, when a woman is found dead in a car that traces back to the Mayor’s motor pool, that partnership comes under fire as the scandal surrounding the investigation threatens to bring down Weldon’s administration