The team investigates the murder of a Marine Captain. When they get there, they learn that a Sergeant came to see the Captain and when he saw him on the floor he entered and was attacked by a man in a mask. He fought him but he got away. They find some fingerprints and identify them as that of a man from Afganistan who is the brother of a known Taliban member. When they learn the man didn't enter the country legally they assume he's terrorist. They find him and when questioned he denies being a terrorist and that he killed the Captain. The Sergeant later tells Gibbs he and the Captain got him out of Afganistan and into the country because he helped them. They didn't go through proper channels because his brother would have killed him fro helping them. Later in Afganistan a Marine is captured by the Taliban and the man's brother posts a video unless his brother is turned over to him, the Marine will be executed. Vance informs Gibbs the SecNav approved the exchange, and he wants Gibbs to bring him and Gibbs doesn't like it. Tony and McGee try to find the Captain's killer.