In "Limelight", a rising young pop star is found dead in an alley, Castle and Beckett delve into the victim’s out-of-control hard-partying lifestyle, but as they dig deeper, a shocking revelation threatens to rock their investigation.
"The Limey" - 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.
Castle and Beckett replicate the '70s to solve a murder.
A robbery-homicide prompts Beckett to invite Demming to assist on a case, giving Castle a ringside seat to their budding romance. When it becomes clear that the two men have very different ideas about how to proceed, the investigation becomes an unspoken competition for Beckett's attention, one in which each man races to solve the case, as Beckett referees between her two admirers.
“Probable Cause” – While investigating a shocking ritualistic murder, Beckett and her team uncover surprising evidence linking Castle to the killing. As the evidence against him mounts, loyalties are tested, and when surprising revelations come to light, Beckett begins to wonder how well she really knows her new lover and partner of four years.
Castle tries to come to grips with the fact that Alexis and Pi have moved in together.
"The Greater God" — The death of a Wall Street puts the team on a collision course with Gates' sister.
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.
"Recoil" - While investigating the murder of a young woman, Castle and Beckett find evidence that links her death with Senator William H. Bracken (guest star Jack Coleman returns), the man responsible for Beckett's mother's murder. Determined to finally bring Bracken to justice, Beckett soon realizes that things are far more complicated than they seem.
There are two sides to every story, and this unique two-parter will explore the same story from each of their perspectives, first from Castle's side as he searches for Beckett in the exciting Season 8 premiere, "XY."