In the sixth-season opener, the team investigates the murder of a Navy petty officer, and Gibbs discovers a link between the case and Vance's decision to break up the team. Eli David: Michael Nouri. Alice Brodie: Jenny O'Hara. Andy Pringle: Eric Jungmann. Michael Rivkin: Merik Tadros. Dallas: Austin Bass.
The probe of a mysterious suicide aboard an aircraft carrier reveals it may be part of a bigger and deadlier plan. Capt. Richard Owens: Chris Mulkey. Taylor Henley: Eric Nenninger. Lt. Eduardo Almeida: James Martinez.
A prominent senator (Tim DeKay) asks Gibbs to solve the murder of a female Navy officer. Lynn Tripp Kiley: Susan Floyd.
Two marines are murdered and the investigation leads Gibbs back to his hometown, where secrets about his past come to light. Ralph Waite guest stars.
Gibbs' search for a marine's killer leads to an encounter with FBI agent Fornell (Joe Spano).
During the week of Halloween, a killer uses the Internet to leave clues about the identity of his next victim.
The team probes a bank robbery that ends with a murder, and Gibbs doubts his own judgment when a rookie is assigned to help in the investigation.
The team must place trust in some shady characters in order to keep a criminal from stealing top-secret government files. Ted Bankston: David Eigenberg.
The team is forced to play a treacherous war game that brings a startling revelation to light.
The team investigates the death of a petty officer, who was killed in a car accident, but the agents suspect foul play. Antonio Sabato Jr. and Tracy Scoggins guest star.
The team must work on a difficult case during the week of Christmas when it's learned the prime suspect has supposedly been dead for 17 years. Ned Quinn: Peter Coyote.
McGee becomes trapped in a women's prison after inmates riot and take over as the team investigates a guard's murder.
Ducky is stabbed while at a crime scene, and the team discovers secrets from his past during the investigation.
The team investigates the murder of a sergeant and uncovers possible treasonous acts he committed that may have led to his death. Kevin Nelson: Chris Carmack.
The investigation into the death of a Marine leads the team into the middle of an inner-city gang war, forcing Gibbs to confront a secret from his past. Mike Franks: Muse Watson. Sgt. Vincente Medina: Kurt Caceres.
A murder reopens a case from Tony's past, forcing him and Gibbs to reverse roles.
A fellow agent is murdered, sending the team to the desert to find a woman who may have answers.
Vance's friend is killed, prompting the director to use Gibb's team for his own private investigation and spurring Gibbs to look into Vance's past. Jackie Vance: Paula Newsome. Joe Banks: Obba Babatundé.
A boy finds a murder weapon, and the team works backward to discover who was killed and the identity of the gun's owner.
Gibbs has no choice but to team up with shifty Trent Kort to pursue one of NCIS' most wanted criminals. Perry Sterling: Christian Clemenson.
Abby is asked to fill in for a missing government scientist who was working on a top-secret project, and the team worries her life is in danger.
Part 1 of 2. Gibbs and McGee work with the NCIS Office of Special Projects in Los Angeles to solve the murder of a marine, and the investigation turns into a national-security case. G. Callen: Chis O'Donnell. Sam Hanna: LL Cool J.
Conclusion. Gibbs and McGee continue their hunt for the terrorist in Los Angeles; and Tony questions Ziva regarding her relationship with Rivkin. G. Callen: Chris O'Donnell. Sam Hanna: LL Cool J.
An ICE agent is murdered during a secret meeting of officials at the home of the SecNav, and NCIS agents must work together with ICE to catch the killer. Julia Foster-Yates: Jaime Murray.
In the sixth-season finale, the team travels to Israel, where Ziva has an uneasy reunion with her father (Michael Nouri); Tony has a confrontation with Rivkin; and Gibbs makes an important decision that reverberates throughout NCIS.