After passing the Captain's exam last season, Beckett was surprised with an offer to run for State Senate. In the action packed season premiere, Castle and Beckett are adjusting to Beckett's career change, when a call from a mysterious stranger sets off an explosive chain of events. 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.

Beckett's side of her abrupt disappearance is revealed. After receiving a mysterious tip from her past, Beckett is launched into a fight for her life, with a team of mercenaries hot on her trail. While Castle investigates why his wife is on the run, Beckett must figure out who wants her dead, before they can finish the job.

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.

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.

Castle and Beckett investigate the murder of a cruise ship entertainer, only to find themselves trapped at sea with the killer.

Castle finally gets his day in court when he takes the stand as the key witness to a murder from five months ago. But when new information suddenly arises, he and Beckett must race against the clock to prevent a miscarriage of justice.

Beckett and the 12th Precinct look into the murder of an English as a Second Language 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.

When a mild mannered safety inspector for the city miraculously survives a poisoning, it might be luck; but when he survives another, it’s a mystery Castle and Beckett will have to solve.

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.