
Naval Criminal Investigative Service Special Agent Leroy Jethro Gibbs leads a group of colorful personalities in investigating crimes -- ranging from murder and espionage to terrorism -- that have evidence connected to Navy and Marine Corps personnel. The team includes MIT graduate Timothy McGee, Ellie Bishop, who specializes in international threat assessment, charismatic and unpredictable Nick Torres, and forensic psychologist Jack Sloane. Dr. Donald "Ducky" Mallard brings his vast experience in forensics into play to help solve cases.
The team links a bizarre crime scene at Arlington National Cemetery to a string of attacks on homeless veterans; Vance orders McGee, Bishop and Torres to complete hours of evidence garage cleanup for withholding information.
The murder of a Marine brings McGee and Gibbs to Los Angeles for a joint investigation with the NCIS office of special projects; Tony looks into Ziva's personal life.
Tony questions Ziva's loyalty to NCIS; Special Agent Callen (Chris O'Donnell) goes undercover; Nate Getz (Peter Cambor) discovers the truth about Special Agent Macy and Gibbs' relationship.
With the weight of the past on their minds, Gibbs and the team go back to work, with DiNozzo and McGee beginning a search for Ziva's replacement.