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.
Tony: One other question, I know you're an expert in English history. And I was just wondering, have you ever heard of Archibald Drummond, the 17th Earl of Trent? Ducky: The Earl of Trent. No, I can't say I have. Why? Tony: I was just wondering. Thanks.