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.

In an effort to help Sam and Deeks return to work, Hetty calls upon Operational Psychologist Nate Getz to help them cope with their traumatic experience. Meanwhile, the rest of the NCIS: LA team investigates the murder of a former Navy Admiral and a controversial journalist aboard a private jet.

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.

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.