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.
The team must locate and retrieve a stolen antiterrorism device before the city is attacked; Hetty is haunted by her past.
Kensi and Deeks go under cover at a rehab center named Tranquility Villa to investigate a Navy officer's death.
Sam and Callen ask an elite Nepali soldier skilled in knife fighting for help retrieving a thumb drive; Deeks and Kensi try to find a balance.
When a former Romanian Communist leader and suspected war criminal is discovered to be living in Los Angeles under a false identity, the NCIS: LA team must locate him before he disappears again.
The team looks for a motive when a senator's daughter (Michelle Trachtenberg) is attacked; a co-worker gives Kensi a perfect gift.
A federal agent's murder is linked to an ancient system of money transfer; Granger and Kensi work with the team from Afghanistan.
The investigation into the murder of two private military contractors ends up putting a member of the team in grave danger; Sam arranges a blind date for Callen.
Callen and Sam search for a murder suspect -- a retired assassin (Danny Trejo) they encountered on their first case together.
The team and an undercover DEA agent must determine if an explosion at a fish market was an act of terror or a smuggling deal gone wrong; a helicopter crash may be tied to Kensi and Granger's search for the white ghost.
When a gang identifies and executes an undercover agent, the team must locate a mole before other agents are put in danger.
Eric witnesses his friend, a computer systems expert, being attacked by people who want information that could redirect a missile; Kensi runs into a familiar face in Afghanistan.
After learning that the Taliban may be responsible for Special Agent Kensi Blye's disappearance, Hetty sends the team to Afghanistan to rescue her.
Nell joins Deeks in the field on a case involving a former Marine who is being tracked by al-Qaida after embezzling money from Iraq.
When an undercover NCIS agent is suspected of working for the smuggler he's supposed to be investigating, the team takes him into custody to find his true intentions.
When software for a new, unmanned aerial vehicle goes missing and the lead engineer's 10-year-old daughter disappears, Sarah is convinced the two are related.
The team investigates when a news reporter names the people responsible for a deadly explosion at a charity event sponsored by the military.