A call from a mysterious stranger ignites an explosive chain of events; the story is first told from Castle's perspective as he searches for Beckett.
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.
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.
In order to hunt down the brutal murderer of a grifting seducer, Castle & Beckett must investigate New York’s elite. Meanwhile, Castle plans to surprise Beckett on their one-year wedding anniversary.
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 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.
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.
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.
Castle and Beckett investigate the murder of a cruise ship entertainer, only to find themselves trapped at sea with the killer.