NCIS Season 42006
The fourth season of the police procedural drama NCIS was originally broadcast between September 19, 2006 and May 22, 2007. Special Agent Gibbs left NCIS at the end of season 3 after a terrorist attack had been successful because his superiors did not heed his warnings in time. The team is now led by DiNozzo for a short time until Gibbs' eventual return. New characters introduced in this season are Michelle Lee, who was briefly on DiNozzo's team and was transferred to the legal department upon Gibbs' return, and Gibbs' former boss and mentor Mike Franks, both as recurring characters. Also, albeit later in the season, Army CID Lieutenant Colonel Hollis Mann is introduced as another love interest for Gibbs. In December 2006, Bill Keveney from USA Today announced that the "CBS investigative drama NCIS topped the Nielsen viewership list for the first time with 17.4 million. CBS was the No. 1 network in viewers and young adults for the week of Dec. 11-17." TV Guide reported on May 5, 2007 that creator and showrunner Donald Bellisario would step down and leave the series due to a disagreement with series star Mark Harmon. Because of Bellisario's "chaotic management style", Harmon threatened to leave NCIS. Co-executive producer Chas. Floyd Johnson and headwriter Shane Brennan replaced Bellisario as showrunner.
When Ziva accidentally witnesses a political assassination, she must surrender to the FBI and deal with the consenquences without Gibbs's help, who is now enjoying his retirement. She learns that the FBI is looking for her and escapes, while the NCIS team, leaded by Tony, must prove that Ziva is innocent. However, when things get more complicated, Ziva seeks help from the one person that always trusted her, Gibbs.
Gibbs is forced to come back out of his retirement to help Fornell, who is being threatened by a convict that escaped from prison. The convict threatens both Fornell and his daughter Emily. Gibbs and the NCIS team re-open the convict's old robbery case, and question a retired sailor who is the only one who contacted the convict after he was sent to prison. The investigation will lead the NCIS team to a surprising discovery.
Singled Out (E3)
An abandoned car is found full of blood, registered to a missing Navy lieutenant. The NCIS team learns that the missing lieutenant was profiling men, trying to find a perfect man for herself. When they find out that the woman intended to go to a seminar at a local hotel, Ziva goes undercover to find more information. Ducky is busy going through the profiles of the men. Jenny makes a secret offer to Tony.
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.
When a burnt and mummified body of a missing and wanted person is found on a Marine base, in a furnace, NCIS must work with FBI. The burnt man turns out to be a serial killer. The both teams visit the man's family and discover something shocking. Also, the NCIS team must deal with the book McGee wrote about them, using "fictional" characters.
When a robotic vehicle named "Otto," a part of a high level project of the Department of Defense, causes a death of a Navy Lieutenant, and then later almost kills Abby, the NCIS team must find out who sabotaged the vehicle and murdered the Navy Lieutenant. Meanwhile, Ziva realizes that Tony keeps on visiting the hospital. What is he doing there?
When a high-level Marine intelligence officer is found murdered in a small motel room, the NCIS team must find the person who murdered him. After discovering that the person was dead for already three days, and that the town authorities already "investigated" the crime, Gibbs is determined to solve the case, which could be related to a terrorist cell, and not let the town authorities get in his way.
Sharif Returns (E13)
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, the team will send Ducky undercover. Meanwhile, another government agency appears to be working on the same case, with different plans.
Friends and Lovers (E15)
When a dead body of a sailor is found in an abandoned part of the town, all the evidence seem to point that the person died from unintentional drug overdose, but when the team uncovers more evidence, it turns out to be a murder. Meanwhile, Tony bonds with a local detective while working on the case.
Dead Man Walking (E16)
When a Navy Lieutenant becomes the victim of radiation poisoning, the NCIS team must find the person who's behind the crime. The Lieutenant, who is working for the IAEA (International Atomic Energy Agency), claims that only his two colleagues knew about his assignment, and whoever it was, the person tried to stop the Lieutenant's next investigation.
When an explosion at a military cemetery mausoleum reveals a crypt full of a mixture of body parts, the NCIS team must inform the families of the victims, hoping to find a connection between the dismembered victims, and narrow down the suspects to find out who is behind the hideous crime. Meanwhile, Abby is dealing with a personal problem, and the only person she can talk to about it is Gibbs.
When a supposedly frozen to death Marine turns out alive on Ducky's autopsy table, the NCIS team has to find out about the victim's movements last few days to uncover what happened to him and who left him for dead. As the investigation progresses, the team learns about the victim's trip to Baghdad via a private cargo plane and discovers a link to Gibbs' past.
Grace Period (E19)
When a weekend call to the NCIS tip line from an unknown source about possible terrorist activity results in the death of two agents sent into a trap, the NCIS team will have to find out who were the people responsible with the help from Agent Paula Cassidy, who holds herself responsible for the tragedy.