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.

The NCIS: LA team must find who compromised a classified vaccine project from a bio tech company. Meanwhile, Deeks struggles with his emotions upon returning to the field.

The NCIS: LA team finds themselves in danger while investigating a kidnapping case of a man claiming to be Callen’s father.

Analyst Nell Jones joins the NCIS: LA team in the field when a former Navy officer’s girlfriend is kidnapped in exchange for Navy intelligence. Meanwhile, Deeks unknowingly 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 goes undercover as a nutritionist and Deeks poses as a new patient at a rehab center to investigate the death of a Navy officer.

Callen and Sam enlist the help of a Gurkha, an elite Nepali soldier specializing in knife fighting, to retrieve a missing thumb drive. Meanwhile, Kensi and Deeks struggle to find a balance in their partnership.

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.

A senator’s daughter is the victim of a home invasion. The team investigate to determine if it was a random crime or a targeted attack due to her father’s crackdown on international cyber warfare. Meanwhile, Kensi’s holiday spirit changes after she receives a surprise Christmas gift.

While in Afghanistan, Kensi and Granger join the team on a joint case when a federal agent in Los Angeles tied to Hawala, an ancient system of money transfer, is murdered.

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.

Following an explosion at a fish market, the NCIS: LA team partners with an undercover DEA agent to determine if the incident is an act of terrorism or a botched drug smuggling deal. Meanwhile, in Afghanistan, Granger and Kensi investigate a helicopter crash that could be tied to their ongoing search for the infamous 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 Special Agent Kensi Blye disappeared and the Taliban may be he holding her captive, Hetty sends the NCIS: LA team to Afghanistan on a rescue mission.

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.

The team takes an undercover agent who is suspected of working for the smuggler he is supposed to be investigating into custody; Kensi and Deeks discuss their relationship.

Sam is convinced that the theft of software for a new unmanned aerial vehicle is connected with the disappearance of the lead engineer's 10-year-old daughter, a girl Sam once provided protection detail for in Saudi Arabia.

When a news reporter announces the group responsible for the deadly explosion at a military-sponsored charity event, the team must investigate her claims and search for the attacker.

When the NCIS: Los Angeles team and DEA uncover the cartel's plans to slyly transport billions of dollars’ worth of cocaine from Colombia to the U.S. using a submarine, Callen and Sam must quickly locate the missing vessel. Meanwhile, Hetty is called to Washington in the aftermath of the controversial mission in Afghanistan.