After Sam's undercover mission in Sudan turns deadly, Callen and the NCIS team must track down their missing agent before it is too late.
After a botched assignment, Hetty is forced to fire Deeks; Kensi struggles with unexpected emotions for her former partner.
The team searches for a dangerous device that was stolen from a college research facility; Sam looks for a popular Christmas gift for his daughter.
Nell goes under cover as replacement for a dead Defense Department researcher; the new NCIS assistant director questions Hetty's leadership.
When a diplomatic service van transporting an unidentified package is hijacked, the team must determine what was stolen and by whom; as Sam and Callen celebrate five years as partners, they face a challenging assignment.
As the team tracks an elusive, chameleonlike killer, NCIS Assistant Director Granger (Miguel Ferrer) critiques every step of the investigation.
Four months after being shot, Agent Callen returns to the Office of Special Projects and joins the Los Angeles team on a kidnapping case.
A case involving the murder of a drug dealer turns personal for Special Agent Sam Hanna when he discovers his former Navy Seal comrades are involved.
The team is assigned to track down a missing unmanned aerial vehicle (UAV) after it is compromised during a training exercise, killing a Marine before it disappears.
When an Iraqi businessman is murdered, the team searches for the former Marine who was hired to protect him.
Following a murder, the secrets to classified software are thought to be lost until NCIS uncovers a suspect from Vance's past.
The NCIS team must find a motive when they discover the body of a Marine who had been living a double life as a wealthy bachelor.
Following the murder of a Russian woman, the NCIS team uncovers evidence that answers who and why Callen was shot six months ago.
While Hetty is at a Senate hearing in Washington, D.C., a murder investigation leads the team to stolen missiles and a dangerous militia group.
Forensic scientist Abby Sciuto (Pauley Perrette) joins the team when a murder case resembles the pattern of a serial killer she has been tracking.
The NCIS team races to solve the murder of a Marine by an exploding cell phone and to find the remaining men of his former EOD (explosive ordnance disposal) unit before another deadly explosion kills someone else.
A petty officer's death leads the team to a teenager in Sam's life; Hetty is concerned about the effect that the workload has on the team.
The murder of a recently released convict forces Callen to go under cover with an old alias.
After receiving a page that an agent needs assistance, the team rushes to a crime scene and learns that one of its own is in peril.
A crime scene poses a security risk when the team discovers the location was used to create a deadly toxin that is now missing.
While opening a safety deposit box at a local bank, NCIS Special Agent Kensi Blye is shot after three armed assailants enter and hold everyone in the building hostage.
When a sailor dies in an underground street race, the team determines that his car, which contained confidential Navy equipment, had been sabotaged; Callen must go to traffic school.
When a Marine is killed in a drive-by shooting, the team fears his younger brother may also be targeted.
When an undercover operation has the NCIS team investigating a MMA gym and its fighters, Sam Hanna is tasked with donning gloves and entering the cage for a one-on-one fight.
LAPD liaison Marty Deeks helps the team find an infamous socialite connected to a Navy officer's murder.
The team races to save one of its own after receiving video evidence of Dominic Vail being held hostage.
The NCIS team is on the hunt for a terrorist who escaped Army custody during a secretive transfer in Los Angeles.
Callen races against a ruthless adversary to locate a woman who knows the whereabouts of a forgotten fortune earmarked to fund a new war in the Middle East and also holds the tantalizing key to his unknown past.
After Callen's cover is blown and it compromises the unit, the NCIS team races to find out who is behind the security breach.