Forensic scientist Abby Sciuto joins the Los Angeles NCIS team when a murder case resembles the pattern for a serial killer she has been tracking.

A crime scene poses a national security risk when the LA team discovers the location was used to create a deadly toxin which is now missing.

NCIS investigates the murder of a Navy officer entangled in the world of Hollywood glitz and glamour as the team is joined at Hetty's request by LAPD liaison Marty Deeks.