Callen is concerned that Sam might be too invested after he takes on a missing persons case for an Afghani elder who helped him years ago when he was wounded on a mission.

Deeks goes undercover to obtain information about an infamous arms dealer looking to get back in the business, but the woman he befriends leads the operation in a dangerous directon. Meanwhile, Kensi confronts new emotions as she runs surveillance on Deeks and his female source.

Sam and Callen need to get their hands on some key evidence after a U.S. Ambassador survives a terrorist attack.

As Callen continues hunting Katya, Kilbride enlists NCIS to help find a truckload of stolen guns. The assignment becomes more challenging when their suspect, the son of a mob boss they believe was planning to sell them, is found dead.