The murder of a Naval Petty Officer leads Gibbs to uncover a shocking connection between the case and Director Vance's decision to disband his team.
While stationed on an aircraft carrier, DiNozzo finds that a Navy Lieutenant's apparent suicide may be connected to a larger, deadly scheme.
The NCIS team becomes entangled in the world of Washington politics when a distinguished Senator turns to Gibbs for help in solving the murder of a young, female Naval officer.
After two Marines are ambushed, the NCIS team finds the investigation leads back to Gibbs' hometown, where secrets about his past are revealed.
The hunt for a marine's murderer puts Gibbs on a collision course with an old friend, FBI Agent Fornell.
During the week of Halloween, a murderous psychopath taunts the team by using the Internet to leave clues to the next victim's identity.
Gibbs second-guesses his own judgment when Vance assigns him a rookie to aid his team's investigation into a deadly bank robbery.
Shocking revelation comes to light after the team is forced into playing a dangerous war game.
The team must rely on information from some questionable individuals to stop a criminal bent on stealing government secrets.
After a petty officer dies in a car crash, the team suspects foul play when their investigation leads them into the violent world of underground street fighting.
While stuck working on a case over Christmas, the team searches for a suspect presumed dead.and begins to discover some startling personal revelations.
McGee is held captive in a women's prison after a guard's murder leads to a takeover.
After Ducky is stabbed at a crime scene, the team uncovers disturbing secrets from the good doctor's past.
Slain sergeant's private life is on full display as the team must determine if a suspected act of treason lead to his death.
While investigating the death of a Marine, the team finds themselves intertwined in an inner city gang war.
Gibbs and DiNozzo reverse roles after a murder leads to one of Tony's old investigations being re-opened.
The death of a NCIS agent leads Gibbs and Tony into the desert to locate a woman who holds the answer to the mystery.
Boxer's death leads Vance to start up his own investigation, causing a sparring match with Gibbs.
When a young boy finds a murder weapon, the team must trace ownership of the gun to find who used it last and who was murdered.
Gibbs and the team must work with the shady Trent Kort to put away one of NCIS's most wanted.
When a government scientist goes missing, Abby is recruited to carry on his work, but the team worries that she may meet the same fate as her predecessor.
The body of a Marine leads Gibbs and McGee to the NCIS OSP division in Los Angeles, where a murder investigation quickly climbs to a matter of national security in which the two offices must work together to resolve. Meanwhile, Tony begins to snoop into Ziva's personal life.
With the appearance of Mossad agent Michael Rivkin, Tony is forced to question Ziva's loyalty to NCIS. Meanwhile, in Los Angeles, Special Agent Callen goes undercover to try to catch a terrorist cell while OSP psychologist Nate Getz discovers the startling truth about Gibbs and Special Agent Lara Macy's relationship.
After a security breach at the SecNav's residence leads to the death of an ICE agent, Gibbs and the team are forced to work with ICE and the FBI to find his killer. Meanwhile, Tony finally comes face-to-face with Michael Rivkin.
Ziva's homecoming to Israel with Gibbs and the team is not a happy reunion with her father, the enigmatic and powerful head of Mossad. As tensions rise, Gibbs is forced to make a decision that sends shockwaves through NCIS.