While Sam and Deeks recover from traumatic torture that will have a lasting impact on their personal and professional relationships, lives are still in jeopardy as the NCIS: LA team searches for stolen nuclear weapons.
Hetty asks operational psychologist Nate Getz (Peter Cambor) to help Deeks and Sam return to work; a controversial journalist is murdered.
The team hunts for a person who jeopardized a classified vaccine project; Deeks must deal with his emotions as he returns to the field.
The team winds up in danger as they investigate the kidnapping of a man claiming to be Callen's father.
A former Navy officer's girlfriend is kidnapped, and demands are made for classified intelligence; Deeks accidentally breaks one of Hetty's rules.
When a 15-year-old hacker compromises missions, Callen goes under cover at a prestigious high school.
The team must alert Homeland Security when they uncover a threat to a Los Angeles-based train during a murder investigation.
Deeks goes under cover to find information on a notorious arms dealer trying to get back in the business.
The Special Projects team travels to Romania to search for Hetty. Meanwhile, Eric and Nell discover that Lauren Hunter, the Office of Special Projects' Operations Manager, is a member of the Comescus.
NCIS teams up with the NSA in an effort to locate the mastermind behind a software program linked to a cyberattack on the Department of Defense.
Sam, working under cover as a bomb specialist, tries to help the team find stolen explosives in the city; Hunter changes the dynamics of the team.
A news reporter's murder leads to an investigation into Libya's rebel movement; Hetty reveals information about Callen's past.
The LAPD asks NCIS for help when a case exposes a link between a Mexican drug cartel and a terrorist.
After a former Navy intelligence officer is murdered, the team's investigation reveals she was living a double life.
The team must establish whether a dishonorably discharged Marine committed a murder or is being framed.
When a Navy ID is found on a body linked to a hazardous material smuggling case, the team goes to Mexico to investigate and search for the missing materials.
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.
The team must find the person behind an ambush on a vehicle carrying Jada Khaled in order to save her and their case; Sam must face Jada for the first time since Sudan.
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.
The team tries to establish Kensi Blye's innocence after she is accused of murdering one of the colleagues of her now-deceased father.
The team searches for evidence of Kensi's innocence after a meeting involving her father's sniper unit turns deadly.
When evidence in a Navy intelligence officer's death points to a team of SEALs about to embark on a mission, Sam must interrogate the group, potentially compromising their operation.
The team helps Nate Getz (Peter Cambor) and the FBI investigate when an ex-Marine is suspected of making a chemical bomb.
Callen, Hanna, Danny Williams (Scott Caan) and Chin Ho Kelly (Daniel Dae Kim) travel from Hawaii to Los Angeles in pursuit of a suspect harboring a deadly virus.
Kensi and Deeks pose as a married couple as they try to expose a Russian sleeper cell in the suburbs.
The L.A. team is drawn into a deadly mind game against a master criminal motivated by Revenge.