Season synopsis
Contains spoilers for this season and earlier seasons.
Beckett’s first day as captain is interrupted by news that her former federal colleagues have been killed. She goes on the run with hacker Vikram Singh, who uncovered the name LokSat. With help from Rita, Castle’s stepmother, they trace the danger to Bracken’s partner and a drug-smuggling operation using intelligence resources. Bracken is murdered in prison before he can provide a way out. Beckett leaves Castle while continuing the investigation, putting their new marriage under strain.
Castle works with Alexis and Hayley Shipton while trying to understand Beckett’s secrecy. She eventually admits that she cannot stop LokSat alone, and they resume their relationship while pretending the separation continues. Castle discovers that his missing memories connect him to the same conspiracy; the couple then openly agree to pursue it together. Defense lawyer Caleb Brown becomes another lead, providing a phone that might expose LokSat, but the attempted contact draws the team into a trap.
Mason Wood appears to rescue Castle and Beckett from an ambush, only to be exposed as LokSat himself. Castle is captured and drugged into naming everyone who knows about the conspiracy. Ryan and Esposito rescue him, and he helps Beckett take Wood down. Back at the loft, Caleb, whose death was staged, shoots Castle. Beckett kills Caleb but is also wounded, and the couple crawl toward one another. A jump forward seven years shows them alive at home with three children, ending the story with their family together.