NCIS (season 4)

After witnessing a Mossad agent perform an assassination, which was not authorized by Mossad, Ziva is suspected by the FBI to be a double agent. Now a fugitive and on the run, Ziva is forced to ask for help from Gibbs, who is in Mexico after retiring from NCIS. Tony finds his leadership skills being tested to the limit as he leads the team to search for Ziva and to prove her innocence before the FBI can arrest her.

Recurring characters: Brian Dietzen as Jimmy Palmer, Muse Watson as Mike Franks and Liza Lapira as Michelle Lee.

A former Petty Officer, convicted of murder, escapes from prison and forces F.B.I. Special Agent Fornell to reopen his case in order to find the real culprit whilst claiming his own innocence. Fornell asks for Gibbs' help, who is reinstated as an NCIS agent by Director Shepard. To his former team's disappointment, Gibbs insists that the reinstatement is only temporary. The team soon finds discrepancies in the Petty Officer's case and that he may have been framed.

Gibbs returns to NCIS and leads his team to investigate the kidnapping of a Navy Lieutenant, who is a computer specialist. They discover that the Lieutenant had used her military knowledge to profile potential husbands and was attending speed dating events. When they suspect that the kidnapper may continue attending the event in order to avoid suspicion, Ziva goes undercover at a speed-dating event to identify him. In addition, Tony is offered a promotion - his own team, as a reward for his performance as team leader while Gibbs was retired - but declines, and remains in Gibbs' team.

A Petty Officer is found dead in his car with "NCIS" written in blood on the seat. The investigation becomes complicated when Homeland Security claims that the Russian Spy suspected of killing the officer is working for them.

When a missing Lance Corporal is found dead in a vacant house, the NCIS team discovers that he was buried in the backyard and then exhumed. They learn about his identity and that he was to be deployed to Iraq, but he never showed up for duty. The investigation leads them to a new clue - he had two fiancées. Abby runs the DNA samples from the two women to find out if the DNA is a match to the soil found on the dead man's body.

It's Halloween and the NCIS team is busy investigating a ransom case. A Marine's daughter has been kidnapped after the kidnapper attacked the Marine in his home. The investigation leads them to a fact that the couple has been separated. They decide to focus on the wife's ex-boyfriend, after learning that the woman is the one who destroyed their marriage. Meanwhile, McGee and Tony are stunned by Abby's Halloween costume.

When a Marine Colonel dies in an explosion at a military golf course, the NCIS team must investigate a suspected terrorist attack with the help from the Army Criminal Investigative Division (CID). The CIA gives them a lead to an abandoned warehouse, but it turns out to be a trap - the warehouse is set to explode. McGee uses his computer skills to break into the secret government files to uncover the terrorist cell while Tony attempts to stop the Marine Colonel's son from joining the Marines to avenge his father's death.

Recurring characters: Scottie Thompson as Jeanne Benoit and Susanna Thompson as Army Lt. Col. Mann.

When an honored Marine veteran is found dead in a hotel, the NCIS team must find out what happened to him. Soon they realize that the Marine didn't commit suicide and that he was homeless. After going through his personal belongings, they find compromising evidence against him, and Gibbs is determined to prove the man's innocence.

When McGee's younger sister Sarah (played by Troian Bellisario) shows up disoriented and bloodied, believing that she might have killed someone at his door in the middle of the night, McGee takes matters into his hands, beginning his own independent investigation but Sarah claims she's innocent although her memory of the last few hours is blank. While McGee works on figuring out what happened to his sister, the NCIS team is investigating a case of a Navy sailor, who is somehow connected to McGee's sister. Both Tony and Abby are busy with love problems, while McGee turns out to have another secret.

Recurring characters: Brian Dietzen as Jimmy Palmer, Scottie Thompson as Jeanne Benoit and Liza Lapira as Michelle Lee.

A dead man in a chimney chute on a marine base leads the team to discover a serial killer's burial ground. They believe that the dead man was the serial killer until Abby uncovers something which proves he may actually be a victim. Meanwhile, Tony helps the director with a special project and makes time for his girlfriend as well while Ducky talks to Gibbs about how he felt betrayed when Gibbs left and after a heart-to-heart the two eventually repair their friendship.

Recurring characters: Brian Dietzen as Jimmy Palmer, Joe Spano as FBI Agnet Fornell, Scottie Thompson as Jeanne Benoit, Liza Lapira as Michelle Lee and David Dayan Fisher as Trent Kort.

A woman is found dead in a classified robotic vehicle she was working on developing. Although it initially looks like suicide, when Abby puts the vehicle through some tests, it nearly takes her life as well. They discover that someone rigged the vehicle to kill the passenger and make it appear to be suicide. They discover that the woman who was killed was not the intended target. Meanwhile, Tony visits the hospital to see his girlfriend and continues working on special projects for the Director. Ziva notices Tony getting calls from the hospital and begins worrying that he is sick.

When a Marine is murdered in a small town hotel room, NCIS is called in to investigate. However, the local Sheriff's department already cleaned up the crime scene and performed an autopsy. They also have a suspect - an Iraqi national who just moved to town a few months earlier.

When the NCIS team learns that the missing 10 kilograms of highly toxic chemical weapons are now in the hands of Mamoun Sharif, a wanted terrorist, they will have to find a way to find the man and stop him before it's too late with the aid from Army Lt. Col. Hollis Mann and constant phone calls from Sharif himself.

After catching an international arms dealer, the NCIS team learns that Navy's highly classified weapons system will be sold to "La Grenouille," an important arms dealer. To stop the transaction from happening, the team sends Ducky undercover. Meanwhile, another government agency appears to be working on the same case, with different plans.

Recurring characters: Stephanie Mello as Cynthia, David Dayan Fisher as Trent Kort and Armand Assante as La Grenouille.

A man proposing to his girlfriend finds the body of a sailor. NCIS works with local officers believing that the man died of an unintentional drug overdose. However, Abby discovers a message written in blood on a laminated card found at the crime scene. Meanwhile, Jimmy continues his relationship with Agent Michelle Lee.

A Navy Lieutenant arrives at NCIS with radiation poisoning requesting that the team investigate his murder. The Navy Lieutenant is an inspector for the International Atomic Energy Agency, so the team tries to figure out who would want to make sure he didn't make it to the next inspection. However, only his two closest colleagues knew where the next inspection was to take place. Meanwhile, Ziva sympathizes with the Lieutenant, in whom she sees a reflection of her own most strongly held beliefs and develops feelings for him. It is revealed in the next episode that the Lieutenant had passed away.

An explosion at a military cemetery mausoleum turns up a skeleton. As they investigate, Ducky discovers that they have turned up the skeleton of more than one body. The team talks to the families to try to find some link between the victims. Meanwhile, Abby is having personal problems.

When the man on Ducky's table turns out to still be alive the unit must track the young Marine's actions prior to his arrival in the morgue. They discover that the marine had been on leave and used his time off for a secret trip to Baghdad. The case takes a turn when Mike Franks - Gibbs' old boss shows up revealing that the young marine is in fact his son.

An NCIS team, led by Paula Cassidy, discovers a tip about terrorist activity but it turns out to be a trap, resulting in the death of two agents and Cassidy, grief-stricken begins blaming herself for what happened. Gibbs and his team are sent to investigate the deaths with Cassidy joining them during the investigation. While Ducky is sure that the man who Cassidy received the tip from was dead at least one day before the explosion, Cassidy insists otherwise. At the end, Paula Cassidy dies in an explosion, much to Tony's sadness.

Recurring characters: Scottie Thompson as Jeanne Benoit, Susanna Thompson as Army Lt. Col. Mann and Jessica Steen as Paula Cassidy.

Director Shepard meets an informant named Troy Webster who has information on international arms dealer La Grenouille but Webster is killed. Shepard later becomes convinced that La Grenouille ordered the kill but the team are all doubting her judgement, believing she might be on a personal revenge trip which is further increased when she manages to lead the team into a trap, leaving them with no clues to La Grenouille's whereabouts after days of investigations.

The assistant of a blind photographer notices a dead Petty Officer in one of the photographs and calls NCIS. Gibbs and his team respond to the case and use the photographer's help to re-construct the crime scene through his heightened senses of hearing and scent to find out who killed the victim. Meanwhile, both Gibbs and Tony are having love troubles.

A man is found dead in a taxi headed to the NCIS headquarters but his body shows no signs of external injuries. Gibbs decides to lead the investigation into the man's death in preference to performing his duties as the Acting Director of NCIS while Jenny is in Paris attending an Interpol conference. When the team discovers that the people whose names were found on a list belonging to the dead man are all dead, Gibbs suspects that the list is a decoy used to distract them.

Jenny returns from her European trip and discovers that she had an unannounced visitor at her home who she suspects is her supposedly dead father. All NCIS agents are scheduled to take a Homeland Security polygraph test, which Gibbs finds out to have been arranged by the CIA. An unarmed Tony and Jeanne are held hostage in the hospital morgue by a drug dealer, who is desperate to remove his shipment of drugs from the dead body packer. Tony eventually meets the man he's been trying to find all these months - René Benoit, also known as La Grenouille who is revealed to be Jeanne's father.