As the hunt for Ziva's replacement begins, Gibbs and his remaining team members must head back to work with the past still weighing heavily on their minds.

The team discovers the bizarre death of a Marine and his two friends may be linked to their past, but its Gibbs who ends up taking a trip down memory lane.

The team must take a second look into the death of a lieutenant after the blogger who accused them of a cover-up ends up dead.

When a Marine's body surfaces halfway around the world, the investigation forces Ziva to dig up a buried chapter of her life.

When a Marine known for his practical jokes is found dead on Halloween Eve, the NCIS team discovers that the victim's "good-natured" pranks may have inspired ghoulish retribution. Meanwhile, Ziva tries to adjust to her new role on the team.

A murder investigation prompts Gibbs and the team to play family counselor to his former mentor, Mike Franks, in the hopes of preventing a bloody international conflict.

With the team's help, Vance faces his demons while uncovering a complex relationship with a killer that puts his whole family in danger.

The team literally finds themselves in the dark when the investigation into the death of a lieutenant is connected to a city-wide blackout.

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 body of the son of a retired Colonel-turned-preacher is found and the team have their suspicions that he may be the victim of a hate crime. Meanwhile, Gibbs gets a holiday visit from his father.

Gibbs is worried about Tony's ability to handle his job when Tony's father turns out to be linked to their newest investigation, an assassination attempt on a foreign prince.

While on the flight back from Paris, Tony and Ziva realize that their assignment to protect a government witness in an embezzlement case is in great danger when they learn that an assassin is located on the same flight.

The team finds themselves in a race against time when a terrorist group threatens to detonate a "dirty bomb" in the D.C. area.

When a Marine is found dead, Gibbs, Fornell and the team hit the open road to bust an illegal trucking operation.

Secrets arise when Gibbs former mother-in-law surfaces as a witness in a murder investigation.

Gibbs and the team investigate the shooting of a Marine and uncovers more to his life than anyone would have ever imagined.

The team discovers striking similarities between themselves and their CGIS (Coast Guard Investigative Services) counterparts when a Navy diver seeking sunken treasure is found dead.

The death of a Navy officer leads Gibbs and the team into the world of high-priced call girls, relying on D.C. Madam Holly Snow to help them catch a killer.

When an NCIS polygraph specialist's night job takes a dangerous turn, Gibbs, Fornell and the team have to uncover the truth.

DiNozzo finds himself increasingly captivated by a woman he's never met while investigating the murder of her brother.

The team tries to track down a serial killer, while Abby heads south of the border to give a speech with McGee in tow.

When a colleague's murder sends shockwaves through the team, Gibbs uncovers a surprising link to the crime.

Gibbs heads to Mexico to face his demons and make a startling decision.