When an FBI agent is killed while trying to track the location of an undercover agent, NCIS must find the missing agent before the criminals he was investigating do.

While Sam investigates the murder of an Iranian exile working to overthrow the current regime, he must also try to save Agent Roundtree, a new agent who's having an unexpectedly adventurous first day on the job, when he accidently triggers a bomb. Also, Nell makes a decision about her future.