Callen pursues every alternative when the Diplomatic Security Service apprehends his father, Nikita Aleksandr Reznikov, as part of an exchange for two American photographers being held hostage in Iran.

Callen and Sam join forces with Anna Kolcheck and the Bureau of Alcohol, Tobacco and Firearms (ATF) when Arkady Kolcheck warns NCIS that a notorious international weapons dealer has returned to the states. Also, the case requires Eric to go undercover as a bank IT technician.