Callen and Sam find themselves trapped inside an armed submarine that terrorists are intending to use to hit an aircraft carrier in San Diego. Hetty goes against orders and forgoes her trip to Washington, as the team attempt to locate and save Callen and Sam and stop the terrorist attack.

The NCIS: LA team find out that one of their own has been compromised as they investigate the murder of a Navy contractor involved in illegal transactions of confidential data.

The Department of Justice target a member of the team. Leon delivers unsettling news to Hetty.

The team learns that someone from their past is targeting one of their own. Nate Getz attempts to help Nell get through a traumatic experience.

Callen and Sam make their way to Mexico to locate the only employee who escaped a professional hit at the Department of Defense. Back in America, the rest of the team work to discover the motive behind the shooting.

Sam is arrested accused of murdering a woman and Callen and Granger attempt to clear his name.

A man is murdered by a small drone, so the team suspect a terrorist group is responsible. Nell attempts avoiding disaster at Long Beach.

After Deeks and Kensi work under cover to investigate the murder of a homeless man they discover a connection to a Mexican cartel.

The team become involved in an investigation into the murders of Marines whose sons are at military academics.

The team take a look at a burglary at a cyber-security company, and Callen has to steer clear after Hetty reveals that his girlfriend, Joelle, is one of the main witnesses.

The team investigate an arms dealer but are interrupted as the suspect's building is overrun by terrorists.

Sam and Callen need to get their hands on some key evidence after a U.S. Ambassador survives a terrorist attack.

Looking for the person responsible for an anthrax poisoning, Sam and Callen work under cover as food truck owners.

Callen and Sam end up being abducted during the follow up of an anonymous tip about a missing NSA agent.

After Sam is shot by a spy contracted by the CIA the team need the help of a Nepali soldier.

Members of the team take a look into the death of an Afghan soldier training in America.

Following a successful sting, an explosion causes three FBI agents to be killed.

When a missile test is hijacked and sent off course, the team searches for the hacking group responsible for the attack with the help of a young computer specialist Hetty brings in to assist the team. Also, Nell sees the bond between the tech guru and Eric and she becomes jealous.Source: CBS

Callen and Sam resume their undercover identities as a prisoner and guard to infiltrate a white supremacist group believed to be in possession of stolen nuclear material, while Kensi transforms herself into a tattooed biker to play the part of Callen’s girlfriend. Also, Callen’s first meeting with Hetty is revealed.Source: CBS

Callen and Sam are shocked when an old acquaintance, who they thought was the recent victim of a murder, appears and asks for their help. As the team investigates, they uncover a possible breach of America's economic sanctions against Russia.Source: CBS

The team attempt to find an expert sniper after they learn about his connection to an extremist group.

Some presumed dead crew members show up from the missing tanker that was involved in Arkady's deal with Russia.

Some of the team have to assume undercover identities in Moscow so that they can locate their suspects.