On Christmas Eve, a Navy Captain is murdered by a group of mysterious assassins, forcing the NCIS team to intervene and also protect his pregnant companion who happens to be the group's true target which eventually leads Gibbs and Ziva into an intense gunfight against the remaining assassins who will stop at nothing in abducting the pregnant Lieutenant while DiNozzo and McGee race to save their colleagues before it's too late while the team also meet Jimmy Palmer's future father-in-law, Ed Slater.