The team learns that someone from their past is targeting one of their own. Nate Getz attempts to help Nell get through a traumatic experience.

After an NSA analyst is found eaten by a shark, the team's investigation leads them to a cartel's money-laundering scheme and sends Callen into a mental asylum to find a key witness; Kensi struggles with her therapy.

After napalm is detected at a crime scene, the NCIS team investigates the sole casualty for possible links to terrorism.

The NCIS team works with the Global Criminal Tribunal when a Syrian seeking justice, David Sarraf, is brutally attacked while delivering evidence that would prove chemical weapons were used on civilians. Also, Kensi stays at the crime scene and comforts Sarraf who is pinned behind a vehicle.

Anna Kolcheck returns to warn Callen that he is in danger and he must now work with an archenemy to stop an underground trafficking ring.