He New Orleans team faces what appears to a bioterrorist attack when a Navy Lieutenant is found dead from an unseen strain of bubonic plague. As NCIS Forensic Scientist Abby Sciuto investigates, NCIS Director Leon Vance dispatches Abby's friend, Carol Wilson and NCIS Special Agent Anthony "Tony" DiNozzo to New Orleans to help. A former SEAL who hunts military impostors is found dead at a museum, and the team's investigation leads them to find the jacket of a Marine who was presumed killed in Afghanistan. When the investigation reveals that the Marine may still be alive, the team travels to Afghanistan in an attempt to bring him home. Meanwhile, Brody wonders about LaSalle's issues with Christmas.