NCIS

While the NCIS team deals with Kate's death, Gibbs' determination to finally put an end to Ari's (guest star Rudolf Martin) reign of terror mounts. Though he has no concrete evidence that the sniper was Ari, Gibbs is haunted by the thought that the bullet that killed Kate was meant for him. As the team works to collect all the evidence they can in an effort to stop Ari, each of them is forced to confront their emotions about Kate's violent death. Meanwhile, the director of NCIS informs Gibbs he will be leaving to take on a new position and introduces him to his new boss, Jenny Shepard (Lauren Holly), a woman with whom Gibbs has a sordid past.

Ari (guest start Rudolf Martin) continues to wreak havoc on the NCIS team as he uses its members as pawns in the game he is playing with Gibbs. Still haunted by images of Kate's death, Gibbs is determined to stop Ari after he and Director Shepard are the target of sniper fire and Ducky is lured out of the NCIS headquarters by the terrorist. Though Gibbs is still uncertain of Ziva's connection to Ari, she becomes an invaluable asset when Gibbs finally comes face to face with his arch nemesis.

Under order from the Governor of Virginia, a skeptical Gibbs is forced to meet with a serial killer he helped to convict a decade before under the pretense that the killer will tell Gibbs where he hid missing bodies and give closure to the families before his death. Gibbs' instinct is correct when the killer is coy and doesn't reveal what he promised. Nonetheless, Gibbs has an NCIS team in place to re-investigate the possible locations of the victims. When a crucial piece of information is discovered, Abby and McGee use their expertise to attempt to pinpoint where the bodies might be.

Gibbs and the team are called in when a recently deceased man is found encased in a Civil War-era tomb. The corpse is that of a missing Staff Sergeant who, according to Ducky, was buried alive. Using cell phone records from a phone found inside the casket, Abby tracks the victim's final phone calls to a bank and safety deposit box that contains a map the Staff Sergeant died protecting. Meanwhile, Director Shepard informs Gibbs that Agent David will now be a full-time member of his team.

When a petty officer is brutally gunned down on the freeway, Gibbs and the team discover that the officer had been living a double life. He had switched identities with a former colleague whose job of illegal transporting gives the team their first lead to the murderer. But the break in the case is short-lived when Abby uncovers a message the Petty Officer left before dying that leads them in an entirely different direction.

Gibbs and the team investigate the murder of a Marine's wife that appears to have been broadcast over the Internet. The team discovers that two bored housewives, whose husbands are serving in Iraq, have been running an Internet sex site from their bedrooms. With both women now missing and an internet file of what appears to be a murder, Gibbs and the team decide to track down the webmaster and follow the money in order to locate the murderer.

Gibbs and the team investigate when a 6-year-old boy informs NCIS his father has been kidnapped. Gibbs quickly develops a unique bond with the young boy whose missing father is a Lt. Commander working as the Navy's liaison with a defense contractor on a highly confidential project called Honor. The NCIS team discovers that the top-secret program, for which the missing Commander holds the only code, has been hacked and classified data has been removed. As the evidence begins to indicate the kidnapping may be a hoax, Gibbs holds his ground when his gut tells him the Lt. Commander is innocent.

When the bodies of two assassins are delivered to NCIS from overseas, Tony and Ziva assume their identities undercover and engage in a sexy rendezvous at a luxury hotel in order to find their target. But while the two are feigning marital bliss in a lavish hotel suite, romantic sparks erupt. Meanwhile, Gibbs discovers that NCIS might not be the only federal agency on the case.

When a portion of a female body is found at Quantico, the NCIS team investigates and is shocked to discover that all the forensic evidence points to Tony as the prime suspect. As Abby questions her faith in her science and her ability as a specialist, she makes it her personal mission to prove Tony's innocence and find out who is trying to frame him for murder before it's too late.

When McGee kills a man while on assignment, the NCIS team steps in to back him when they discover the man was an undercover police officer. Gibbs is furious when Director Shepard overrules him and allows the police to run their own investigation on McGee. Determined to clear McGee's name and prove his actions were justified, the NCIS team bands together to protect one of their own. Meanwhile, Tony gets a troublesome phone call from his past.

Gibbs and the team investigate the murder of a supermodel filming a reality TV show on a Marine base. At the start of the investigation, the team believes the model may have committed suicide, but they uncover a twisted love triangle involving the Marine staff sergeant working on Boot Camp Babes, a drug addicted ex-boyfriend and a disgruntled adoptive father, who is also the executive producer of the reality show. Meanwhile, Director Shepard is annoyed when Gibbs doesn't show up at an awards ceremony where he is being honored.

Gibbs and the team rush to find Tony and Ziva, who get trapped in a container at a shipyard after seeking refuge from a shoot-out. While inside, they uncover counterfeit bills being used to bankroll a terrorist operation. Meanwhile back at NCIS headquarters, Abby struggles to locate the two agents when the GPS chips in their cell phones show they are out of range.

Gibbs and the team are called in on a weekend when a Navy Lt. Commander in charge of a shipment of nuclear weapons is apparently abducted. The team works to piece together the Lt. Commander's location by tracking a distress call she made from her cell phone. Believing her captors have abducted the Lt. Commander to commandeer the nuclear shipment, NCIS must move quickly to find the missing woman and protect the classified location of the weapons.

When the wives of two Marines are murdered, Gibbs and the team are called in to investigate. Gibbs and the team fear the murders are racially motivated since the two women are Asian. The team works together to find the killer and protect another woman and her newborn baby who they fear are the next targets.

The NCIS team is shocked when they discover the severed head of a Marine at an illegal automotive chop shop run by Marines. When the Marines running the stolen car ring are ruled out as suspects, the team looks for clues that will lead them to the rest of the Marine's body and the person responsible for the crime.

The team investigates the mysterious explosion of an ambulance that is supposedly carrying the remains of a Marine killed in a car crash. As the team works to confirm the identity of the Marine's remains, they discover the ambulance was rigged to explode and that the DNA of the victim does not match that of the deceased Marine. As Gibbs pushes the team to figure out who the victim is, he discovers that the family of the missing soldier is keeping a secret.

Gibbs and the team are called to investigate when a group of teens on a nature hike discover Marine dog tags in a national forest. When they search the missing Marine's campsite, they quickly determine that the Marine was not alone and they begin to search for his camping partner, a woman who they hope is still alive. As the investigation progresses, the team discovers that a number of past accidents in the park seem to be linked to a possible serial killer who is using the national forest as a location to torture and kill women.

Gibbs and the team are called in when a teenage student at a Quantico base high school attaches a bomb to his body and holds his fellow students hostage. In order to establish contact with the bomber and his hostages, Gibbs manages to get into the classroom and leaves Tony to act as lead on the mission. With snipers poised to take the teen down, Gibbs realizes that the 17-year-old might not be acting on his own, and the NCIS team races to find out who may be controlling him from the outside.

Gibbs and the team are called in when a couple of kids stumble upon the body of a missing Marine in a frozen lake. As the team searches the frozen lakebed for clues, they come across three more bullet-ridden bodies. During the autopsies, Ducky and Gibbs discover that the three additional victims had gang tattoos. With this crucial piece of information, the team works to uncover the Marine's connection with a deadly street gang.

Gibbs and the team are called in when a Pentagon cryptographer suspected of spying apparently commits suicide. With their prime suspect dead, the NCIS team must uncover whether or not she was the Pentagon's mole. The team quickly discovers evidence that indicates the young woman was not alone when she died. Now faced with a potential murder, Gibbs and the team follow the clues left behind to find her killer and expose the mole.

After discovering that a grisly murder scene was staged, the team realizes that Abby was the intended target when some key evidence contaminates her lab and almost kills her. The NCIS team soon learns of some unsavory characters in Abby's past and must work quickly to uncover who is out to get her.

Ziva is in shock when a routine tactic she uses to subdue a suspect might be the cause of his sudden death. As Ducky and Abby work to clear Ziva's name, Gibbs learns that Director Shepard has been kidnapped by their dead suspect's brother. The man demands the release of his brother, who he doesn't know is dead, in exchange for the NCIS director.

The members of NCIS are distressed when Gibbs is injured in a terrorist explosion while on assignment. As the team attempts to put their feelings about Gibbs' injury aside and work on the investigation, Tony steps into the role of senior agent, causing a bit of resentment from other team members. Meanwhile, while recovering, Gibbs is flooded with memories of a past that he had long struggled to suppress.

As the team tries to track down the terrorists behind the bombing that injured Gibbs, they learn that the terrorist group is planning another bombing of 9-11 magnitude--and that Gibbs has information about their plan. Meanwhile, Gibbs receives a visit from his former boss and mentor that conjures up suppressed memories. As Gibbs regains his memory, he finds himself on a race against the clock to fill in the gaps and stop the terrorists.