A critic of the NCIS has severely complained about an alleged cover-up of the death of a Naval officer; the griper falls to his death; both the NCIS and the Metro PD investigate; the Gibbs team figure it out. Ziva seeks Gibbs's signature.

In Washington, DC, near the Capitol a van accidentally hits and critically injures a pedestrian, who proves to be The Cooler, a wanted contract assassin, whose next target appears to be a Navy lieutenant commander; Gibbs and company investigate the target, LCdr. Geoffrey Brett, and his circumstances, including the threat. The Cooler briefly regains consciousness in a hospital, then dies before an NCIS agent reaches him. Ziva acts as Brett's protective escort, but he ditches her. Tony and McGee meet a CPA, then she dies. The three musketeers gather pieces of evidence and, with Gibbs, put them together; Brett says that he needs a lawyer. Meanwhile Abby volunteers to become an organ donor, learns more about herself, visits a pet-rescue center, meets someone whom she admires, examines her own feelings, and has a serious chat with Gibbs.

When an undercover cop suddenly reappears after faking their death 10 years earlier, chaos ensues.