Beckett and the 12th Precinct look into the murder of an English as a Second Langue student. But when the victim’s class won’t talk to the police, Castle goes undercover as a French Canadian immigrant and learns that the victim was more than he seemed.
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 priceless work of art is stolen and its transporter murdered, Castle and Beckett must work with the key witness to track down the painting and sniff out the killer.
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.
Detective Slaughter (guest star Adam Baldwin) returns to enlist Castle’s help in solving a high-stakes robbery case. But when a body is found linked to the crime, Slaughter becomes the number one suspect in the heist turned murder, while Castle has to determine whether he’s guilty or help to prove he’s innocent.
Castle thinks the Antichrist maybe involved in the death of an axe wielding psychiatric inmate who drops dead in the P.I. office.
A clue at the scene of the death of an armored-car driver leads Beckett and Castle back to an old case solved by Esposito. But complications arise when they learn that Esposito might not have been telling them everything about his past with the culprit.
With their best lead in hand, Castle and Beckett are ready to take on LokSat. But an unforeseen twist puts their case – and their lives – in jeopardy.
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 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.