Gibbs' obsession with finding the terrorist Ari (Rudolf Martin) reaches its zenith, and is timed perfectly, as Ari is training men for an attack on Marine One with President Bush and Prime Minister Sharon on board.

Gibbs' team investigates the death of a SEAL during a training exercise, and come to suspect that it wasn't an accident, but a murder.

When a Marine is killed with a specialized military weapon, the agents investigate the illegal weapons market and find an undercover ATF agent (Bellamy Young) also working on the case, and Gibbs asks her to work with them to find the killer.

The NCIS agents search for a missing marine, who unbeknownst to them, is being tortured in a cell by a mysterious captor.

The team investigates the murder of one of their own, an NCIS agent who was working on a cold case when he was shot and nearly disemboweled.

Gibbs and his team search for a former Navy SEAL who escaped from Leavenworth, where he was serving time for killing his wife and her lover.

Gibbs is frustrated by the mystery surrounding the discovery of a dead petty officer who was dressed after he died and stuffed in the ceiling of a nightclub.

Ducky and Gerald are held hostage in the autopsy room of NCIS headquarters by an armed intruder (Rudolf Martin), whose purpose is unexplained.

The FBI asks Gibbs to find his former Marine C.O., who they've accused of stealing money from a mission in Iraq. But Gibbs is convinced that the man who trained him is innocent.

The team investigates the murder of a Naval officer who was shot as he tried to help a stranded motorist.

The team investigates the murder of a Marine recruitment officer, who was killed, as the team discovers, by a highly skilled sniper.

The discovery of a leg with a Marine tattoo on the calf leads the team to a small town where they uncover a murder scheme involving deception and greed.

A Naval officer hired by an outside agency to test a product for possible Navy use is murdered, and Gibbs finds that the case is cloaked in secrets and deceptions.

A woman (Sherilyn Fenn) digs herself out of a shallow grave and doesn't know who she is, but is convinced that a bomb is on board a Navy ship.

Gibbs and his team investigate when a dead Marine's wife receives a call from someone claiming to be her husband.

A Navy translator dies mysteriously soon after returning to the U.S. from Guantanamo Bay, and the investigation takes the team to Cuba.

The discovery of the body of a Navy submariner whose features are all but obliterated leads Gibbs to believe a terrorist has stolen the man's identity and is aboard a sub.

An NCIS agent (Joel Gretsch) who worked for Gibbs asks his help in the case of a seaman (Charlie Hofheimer) who tests positive for methamphetamines, but claims he never took the drug.

A hunter discovers a cargo pod stuffed with the mummified body of a Naval officer who vanished in 1994 and was believed to have stolen money from his ship.

A Navy seaman is found at the bottom of the ocean in his dress whites with a ceremonial sword around his waist, attached to weights.

When the bodies of a Navy commander and two drug dealers wash up on the beach near each other, everyone, except Gibbs, believes the commander was involved in a drug deal.

A Marine dies when his parachute fails and he crashes through a car during a training exercise, and Gibbs suspects he was murdered.

A Marine mysteriously drops dead aboard Air Force One and jurisdiction problems force Gibbs to share the investigation with a Secret Service agent.