The team investigates the death of a retired Navy Lietenant, forcing Ducky to reveal his membership in a secret society that looks into cold cases on NCIS. "16 Years" is the seventh episode of the show's 13th season.
McGee: Rule number 70 - keep digging till you hit bottom. Abby: McGee! There is no rule 70. McGee: Well, I-- Abby: You just made up a rule. This McGibbs thing has really gone to your head. I don't even recognize you right now.