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.
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
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.
When Castle and Beckett wake up in bed, handcuffed together, in a locked room with no memory of how they got there, they must piece together the mystery of where they are and why, all while trying to escape. But as the two of them adjust to being shackled together, what's the biggest threat they face... the people who abducted them or each other? Meanwhile, Ryan, Esposito and Gates are left to investigate their disappearance in a case where all is not what it seems.
A sniper on a killing spree is terrorizing New York City. With the clock ticking down to the next murder and nothing to go on except a killer with no apparent motive but to instill terror, this could prove the team's toughest case yet. The hunt is made even more complicated when Beckett begins to experience increasingly strong moments of PTSD - moments she tries hard to hide from Castle and the detectives.
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 Castle and Martha are taken hostage by a crew of bank robbers dressed in hospital scrubs and using classic television doctor names (Trapper John M.D., Dr. Huxtable, Dr. Quinn Medicine Woman and Dr. Doogie Howser), Beckett finds herself on the outside, desperately trying to rescue them -- which proves to be even more difficult with a by-the-book hostage negotiator (guest star Dean Norris, "Breaking Bad") watching her every move. Castle becomes the de facto leader of the hostages, which includes Barry Livingston ("My Three Sons"), and discovers that the robbery is actually a skillfully orchestrated distraction for an even more sinister plan. But with Castle stuck on the inside and Beckett on the outside, will either be able to foil the bank robbers' plans before it is too late?
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.
Castle & Beckett work a murder case around the theft of a valuable sculpture. Kristin Lehman ("The Killing") guest stars as Serena Kaye, a smart, sexy insurance investigator, who joins Castle & Beckett in the investigation, but she also has her eyes set on Castle, all the while hiding a very important secret from the team. Jessica Tuck ("True Blood") also guest stars as Joy McHugh, a wealthy museum benefactor who becomes a suspect in the murder investigation.
While investigating the mysterious shooting death of a young woman, Castle and Beckett face a cop's worst nightmare when they discover that the gun used in the killing is Det. Ryan's old service weapon - the one that was stolen by the serial killer, 3XK. Now with the clock ticking, the team must work to solve the murder, track down 3XK and retrieve Ryan's gun before the killer strikes again.