While Callen suspects Hetty of keeping secrets about his past and Joelle surfaces in her quest to capture Katya, NCIS must track down an informant whose life is in danger. Also, Kensi and Deeks work to expand their family.

Sam and Kilbride clash when a case involving an arms dealer responsible for the slaughter of ATF agents leads them to a well-connected General and friend of Kilbride, accused of supplying militia groups with guns. Also, Kensi and Fatima go undercover at a rehab facility to question the arms dealer's girlfriend.