NCIS

As each team member deals with the absence of a retired Gibbs, Ziva's past comes back to haunt her when she inadvertently witnesses the assassination of a military attache by her former Mossad partner. Convinced her father ordered the hit, Ziva seeks refuge at the Israeli Embassy, only to find she is wanted by the FBI. As the NCIS team, now headed by Tony, works to prove her innocence, Ziva reaches out to the one person she has always been able to trust.

When a convict from FBI Agent Fornell's past escapes and threatens not only him but his young daughter, Gibbs comes out of retirement to re-open the convict's armed robbery case. With his former team by his side, Gibbs questions a retired sailor who appears to be the only one who has any outside contact with their wanted man since his incarceration. But as the investigation progresses, the NCIS team discovers the man they are hunting for is out for something other than vengeance. Hal Holbrook guest stars.

After the team learns a missing Navy lieutenant had been profiling men to find herself the perfect mate, they trace the woman's path and discover she planned to attend a singles seminar at a local hotel. Ziva goes undercover to gather information on the male attendees with hopes that one of them will lead the team to the missing Lieutenant before it's too late. Meanwhile, Director Shepard makes Tony a secret offer.

After the team learns a missing Navy lieutenant had been profiling men to find herself the perfect mate, they trace the woman's path and discover she planned to attend a singles seminar at a local hotel. Ziva goes undercover to gather information on the male attendees with hopes that one of them will lead the team to the missing Lieutenant before it's too late. Meanwhile, Director Shepard makes Tony a secret offer.

When the team investigates the case of a dead Lance Corporal found by a real estate agent, they realize the body was buried in the backyard and then exhumed. After determining his identity, they learn the Marine, who was deployed to Iraq but never showed up for duty, had two fiancees. Abby uses her technical knowledge to run DNA samples from the two women and soil from the grave while Ducky uses his newly obtained Masters in forensic psychology to help NCIS implicate the killer.

After receiving a ransom call from the kidnapper of a Marine's daughter, the NCIS team learns that the girl's parents were recently separated after a marital indiscretion by the wife. Armed with that new information, Gibbs and the team focus their investigation on the woman's ex-boyfriend. Meanwhile, Abby's Halloween costume renders McGee and Tony speechless.

When an explosion kills a Marine Colonel on a military golf course, the NCIS team must work together with the Army Criminal Investigative Unit to find the killer. After a CIA tip leads them to an abandoned warehouse rigged to explode with a cell phone bomb, McGee uses his computer skills to tap into secret government files in order to track down the CIA informant and uncover the terrorist cell. Meanwhile, romantic sparks fly for both Gibbs and DiNozzo.

When an explosion kills a Marine Colonel on a military golf course, the NCIS team must work together with the Army Criminal Investigative Unit to find the killer. After a CIA tip leads them to an abandoned warehouse rigged to explode with a cell phone bomb, McGee uses his computer skills to tap into secret government files in order to track down the CIA informant and uncover the terrorist cell. Meanwhile, romantic sparks fly for both Gibbs and DiNozzo.

After McGee's sister appears at his door bloodied and confused, he struggles to piece together her whereabouts the night before. Soon he discovers that the NCIS team is investigating the murder of a Navy sailor who had a previous relationship with his sister. Meanwhile, as separate clandestine romantic relationships bloom for both Abby and Tony, the NCIS team discovers McGee has a secret of his own.

The NCIS team begrudgingly joins forces with the FBI when they identify the remains of a man on a Marine base as a serial killer the FBI has been hunting for 12 years. After contacting the serial killer's family, the NCIS and FBI teams search their home for additional remains and make a shocking discovery. Meanwhile, the NCIS team has problems with the "fictional" book McGee wrote about a team of NCIS agents.

When a highly classified robotic vehicle called "Otto" causes the death of a Navy Lieutenant, Gibbs and the team initially think the cause of death is suicide. But when Otto apparently malfunctions and puts Abby's life at risk, the team realizes that the vehicle had been sabotaged and the Lieutenant was murdered. Meanwhile, Ziva is concerned by Tony's secretive trips to the hospital.

Gibbs and the team rush to a scene where a high-level intelligence officer was murdered, only to discover that the crime took place three days earlier and was "investigated" by the local authorities. As the case unfolds, the NCIS team discovers evidence of a potential terrorist cell, but Gibbs is wary since small town biases seem to sway the initial investigation.

After 10 kilograms of highly toxic chemical weapons go missing, Gibbs and his team scramble to locate it. The NCIS team is horrified when they discover that the deadly chemical weapon is now held by wanted terrorist Mamoun Sharif. As Sharif taunts them with phone calls, Gibbs and the team unite with Army Lt. Col. Hollis Mann (Susanna Thompson) to find him before he carries out his plan to attack major U.S. cities with chemical warfare.

After capturing one international arms dealer, the NCIS team discovers that the Navy's highly classified weapons system is about to be sold to another high priority arms dealer known as "La Grenouille" (Armand Assante). Using Ducky as a decoy, Gibbs and the team set up a meeting with the elusive criminal. But just as NCIS is about to make their move, they discover that another government agency has other plans for Le Grenouille. Meanwhile, Gibbs' curiosity is peaked when Jenny appears to have a personal vendetta against their wanted man.

Working with the local officials, the NCIS team originally believes a the sailor died of an unintentional drug overdose in a seedy part of town. But when they uncover a mysterious laminated card, Abby discovers an ominous message written on it in blood that quickly makes the team switch gears to find the sailor's murderer. Meanwhile, Tony bonds with one of the local detectives working on the case.

Gibbs and the team collaborate with an inspector for the International Atomic Energy Agency suffering from radiation poisoning, recreating his routine in an effort to figure out when the contamination took place. Gibbs is convinced that whoever is responsible for the poisoning was trying to ensure that his next scheduled inspection would not happen. But when the dying man insists that only his two closest colleagues knew of the upcoming trip, the team works to find the culprit. Meanwhile, Tony is surprised when he sees a softer side of Ziva.

When Ducky and Abby confirm that they have identified the remains of at least five people, the NCIS team immediately begins notifying the families in the hopes of making some connection between the seemingly random selection of victims. But when the suspects are narrowed down, even Gibbs is surprised with the final outcome. Meanwhile, Abby turns to Gibbs with a personal problem.

The NCIS team investigates when a marine thought to have frozen to death wakes up on Ducky's autopsy table. With the young Marine on life support, the NCIS team tracks his movements in the days before he was left for dead and discovers a secret trip to Baghdad via a private cargo plane and a link to Gibbs' past.

Gibbs and the team investigate when a weekend call to an NCIS tip line results in the death of two agents. The NCIS team discovers a tip about terrorist activity was a trap that resulted in the death of two agents. Blaming herself, Agent Cassidy works with the NCIS team to track down the people responsible.

Gibbs and the team investigate when McGee's fictional book about an NCIS agent becomes reality. McGee is horrified when a Petty Officer on whom he based the character for his latest book is murdered. With little to go on, the team pushes McGee to figure out who could have accessed his secret manuscript.

Director Shepard takes a huge risk and agrees to meet an informant alone about Le Grenouille, but the meeting goes bad and her contact is killed. Gibbs and the NCIS team attempt to gather the information the man was going to supply or risk losing their nemesis once again.

Gibbs and the team investigate when a blind photographer inadvertently captures the murder of a petty officer on file. With little evidence, the team turns to Scott (Billingsley) to re-create the scene of the crime using his heightened senses of hearing and scent to track down the Petty Officer's killer. Meanwhile, Tony and Gibbs struggle with personal relationships.

Gibbs ignores the bureaucratic paperwork associated with his "acting" director duties and leads an investigation for a murder victim found in a taxi headed to NCIS headquarters. Meanwhile, Jenny discovers a secret about her past.

As the NCIS Director returns from a controversial European junket, and Gibbs and his agents reluctantly prepare for Homeland Security polygraph tests, tightly woven secrets among the team unravel. In addition, an unarmed DiNozzo and his girlfriend are held captive by a merciless drug-dealer.