A detective of the Metro PD approaches Gibbs on the day before Christmas Eve while investigating a burglary and double homicide involving an older couple in their upscale home. A delivery driver saw a third person inside the house; fingerprints at the scene lead to a former Navy hospital corpsman second-class (HM2), Quinn, who served in Vietnam with The Walking Dead, and who supposedly died 17 years before; Ducky signed the death certificate for Quinn. Abby sees Santa Claus and makes a picture of herself with him. Gibbs, acting on a suggestion by Ducky, finds Quinn at the The Wall; then the gang get a project for Christmas Day; Tony finds an unpleasant Christmas gift. The Metro cop rushes to nail Quinn, but the team believe otherwise, and they persist in their efforts; Gibbs, Tony, and Ziva meet the cop at the scene, and the real bad guy joins them, so they bust him. McGee gets a shock; Gibbs makes a delivery and a telephone call.