Gibbs' worst fears are confirmed when he learns that his nemesis, Arab/Israeli double agent Ari (Rudolf Martin), is back in Washington D.C. on assignment to kill him. Ultimately, the NCIS team discovers that Ari has a bigger plot... and they end up paying the ultimate price trying to thwart it--the death of a team member.

When a letter sealed with a kiss is delivered to NCIS, Tony assumes it's for him and opens it, only to release a mysterious powder into the NCIS squad room.

Gibbs and the team work to clear the name of a Navy medic killed in Iraq, who is the prime suspect in a murder in his hometown.

Gibbs and the team head back to school when a Marine in an ROTC program is found murdered on a college campus.

The NCIS team investigates when a Petty Officer commits suicide after being institutionalized for a nervous breakdown.

The NCIS team investigates when a petty officer who recently returned from duty is found dead backstage at a local bikini contest.

The NCIS team investigates when a pair of blue eyeballs are sent to a sailor in D.C. in a package from Paraguay.

The NCIS team investigates the bizarre death of a female petty officer who is found brutally murdered in the bed of a dance club bartender.

The NCIS team investigates when a Marine records his own murder on video as he falls off a cliff.

Gibbs gives McGee a shot at running a case when the NCIS team is called to investigate when a woman claims to have witnessed the murder of a sailor.

As he reassembles the pieces of three bodies found stuffed in barrels months ago, Ducky is shocked when he discovers their identities.

The NCIS team investigates the possible murder of a petty officer that was reported by a telemarketer who heard it over the phone.

The NCIS team investigates when the body of a naval officer missing for 2 years turns up on the bottom of a lake.

The team must work together to find Tony when he disappears during an undercover operation.

Gibbs and his team are called to the scene when a Marine's wife kills an intruder who tried to rape her.

Gibbs and his team are summoned to examine the mysterious death of a Navy commander who, after successful open heart surgery, seemingly bursts into flames.

Gibbs and his team must clear the name of an elderly Marine who confesses to murdering his best friend nearly 60 years ago.

The NCIS team protects an Iraqi War veteran who is the target of terrorist threats.

Body found on a Marine firing range leads the team to discover a Mafia dumping ground.

The NCIS team is called in to investigate when a body dressed as a Navy lieutenant is discovered apparently raped and murdered.

The NCIS team is called in to investigate when a perfectly functioning Marine helicopter is found in the middle of a crop circle.

The NCIS team is called in to investigate when the decomposed body of a woman in a wedding dress is found in a cell beneath abandoned military housing.

When the wife and 9-year-old blind daughter of a Navy captain are kidnapped, Gibbs and his team are faced with a unique challenge.