When the murder of an Army veteran puts Beckett on the trail of the man who shot her, Castle struggles to keep Beckett safe.
Lilly receives a home movie in which a runaway teen is apparently shot and killed, prompting her to take another look at the 1979 case.
After receiving a page that an agent needs assistance, the team rushes to a crime scene and learns that one of its own is in peril.
When a renowned surgeon comes to St. Bonaventure for treatment, the team’s enthusiasm is quickly overshadowed by the doctor’s behaviour.
When the CIA informs McGarrett that his mother has gone rogue on her undercover mission and may have killed her partner, Steve goes to Mexico to bring her home and prove her innocence.