When the NCIS: LA team learns that someone from their past is targeting one of their own, they desperately search the city. Meanwhile, Operational Psychologist Nate Getz visits Nell to help her through her traumatic experience.

When Sam is arrested for murdering a woman, Callen and Granger work to clear his name. Meanwhile, Kensi and Deeks discover a link between the victim and a student from Sam's past.