Two passersby find the scene of a one-car crash and the bodies of a Marine lance corporal and a young woman; Gibbs and company investigate; Ducky presents a "two-pronged curiosity", and he says that the event may not be either simple or an accident. Abby starts to have flashbacks about a very early case, which still bugs her. Ziva learns that the fathers of the victims experienced a mutual problem 10 years ago while serving aboard the Marine Corps Base, Quantico, Virginia; the gang interview the parents, and the fathers show much anger and hostility toward each other; Gibbs and Ziva learn about the feud. McGee has a chat with Abby. Gibbs, Tony, and Ziva check out a cousin and his pad and his gear; Tony finds a suspicious object; they get both a solution and the bad guy. Gibbs also chats with Abby, who seems to understand better and feel better.