Season synopsis
Contains spoilers for this season and earlier seasons.
Castle is found at sea two months after vanishing before his wedding, with no memory of the missing time. Beckett investigates evidence that appears to implicate him in his own disappearance, while Castle tries to reconstruct what happened. Their delayed marriage finally takes place in the Hamptons with Jim, Martha and Alexis present. A later case at an Arizona ranch gives them an improvised honeymoon, though the mystery of Castle’s absence continues to follow them.
After his cooperation with a Mafia boss costs him permission to work with the NYPD, Castle gets a private investigator’s license. His cases still intersect with Beckett’s, and Jerry Tyson and Kelly Nieman return to target her. Castle makes himself bait for Tyson, allowing Esposito to shoot the killer, while Beckett escapes Nieman and kills her. Castle is reinstated at the precinct. He also recovers part of his missing history: an intelligence operation used his connection to a former schoolmate, then suppressed his memories.
A murder in the woods brings Castle back to the masked killer he encountered as a child, an experience that helped make him a crime writer. The investigation leads to a psychiatrist whose voice Castle recognizes. Inside the man’s barn, Castle discovers evidence of his victims and is attacked; Beckett passes him her gun, enabling him to stop the killer. Beckett, meanwhile, passes her captain’s exam and receives an invitation to pursue a state Senate seat. The season ends at Castle’s writing-award ceremony, with the couple considering what comes next.