A showdown between the NCIS team and an elusive arms dealer reaches an explosive conclusion.
Ducky makes a startling discovery that leads to the search for a missing child; Tony struggles to deal with his feelings for Jeanne.
Gibbs and Lt. Col. Mann investigate the murder of a Marine captain who had access to highly classified information; a witness in the case turns out to be Gibbs' ex-wife.
Gibbs and the team realize that a cadaver mistakenly tagged as a John Doe is actually that of a career felon with ties to a criminal mastermind.
A suicide attempt turns into a murder investigation when the team must talk a distraught naval officer out of jumping off a roof.
While investigating a death aboard a top-secret naval research ship in the middle of the ocean, the team discovers an abandoned ship and a deadly secret.
Gibbs finds himself on an emotional journey into his past when he agrees to help the childhood friend of his now-dead daughter.
While investigating the assassination of a Navy admiral, the team meets a woman searching for her husband, a political refugee from Africa.
The search for a trained survivalist wanted in connection with a cold-case murder leads the team into the wilderness.
The team believes a Marine is being groomed to become a supersoldier.
Ducky refuses to autopsy a Muslim Marine found dead near a mosque that the FBI suspects of terrorist recruitment.
The team stakes out a warehouse to catch a suspected thief but ends up witnessing a murder; Ducky keeps a secret from the team.
Abby risks her career in defense of a dog that authorities believe is behind a fatal mauling; Gibbs tries to ferret out the secret Jenny is keeping.
When the dead body of arms dealer La Grenouille is discovered, the FBI investigates the NCIS team, and Jenny Shepard becomes the prime suspect.
Two members of the team are sent to Iraq when a mortar attack in Baghdad turns into a murder.
Ziva's undercover assignment turns deadly when the serial killer she is tracking becomes suspicious of her.
Jimmy Palmer becomes the target of a killer who only he can recognize.
When an ex NCIS agent is found dead, the entire team is put in danger in the hunt for the killer.
The team hunts for the killer of a special agent and suffers grave consequences.
The team hunts for an agent's killer and suffers grave consequences.