A murder investigation of a Navy Admiral takes a shocking turn when a woman, a political refugee, returns home to search for her husband.

After a young Muslim Marine is murdered near his Mosque, Ducky refuses to perform autopsy due to his religious beliefs, so the NCIS team tries to talk to the father of the deceased, and they send McGee to plant a bug in the Mosque, only to discover that the FBI already planted their bug.

The dead body of La Grenouille finally surfaces and the entire NCIS is put under the investigation by the FBI, with Jenny as the prime suspect for his murder.

Demons of the past come back to haunt Gibbs when he finds a cryptic message waiting for him at a crime scene.

Dead Marine's day job at a government think tank leads Gibbs and the team into the life of a 12-year-old prodigy who may be the killer's next target.

The team hopes to avoid an international incident when an American officer is killed on a British ship.

Gibbs and the NCIS team partner with a Coast Guard Investigative Service (CGIS) Agent to solve the murder of a Marine gunned down on a dinner boat.

To Gibbs' displeasure, Special Agent E.J. Barrett returns to lead the investigation of a seaman's death that may be connected to a series of port-related murders. Meanwhile, Ziva finally introduces her boyfriend, Ray, to the team.

After a warehouse fire reveals missing Navy documents, posing a potential threat to national security, the NCIS team joins the Baltimore P.D. investigation, reuniting Tony with a boy from his past.