Callen embarks on a secret project, leaving Sam and the entire team in the dark. After Hetty demands his operation be shut down, the team is tasked with locating Callen before he finds himself in over his head.
DEA agent Talia Del Campo turns to the NCIS: Los Angeles team for help after her partner is murdered. Also, after Kensi grows suspicious that Deeks is hiding something, he surprises her by introducing her to his mother.
A 20-year-old Peruvian massacre is investigated after a famous fashion model, believed to be one of the survivors, becomes a potential target. Kensi goes undercover as the model's assistant, while Deeks poses as her chauffeur.
Callen and Sam are forced to work on their day off when they mysteriously receive a cell phone and the caller threatens the lives of innocent people if they don't do exactly what he says.
NCIS Special Agent DiNozzo partners with the NCIS: Los Angeles team to search the city after his prisoner escapes custody on a flight from Singapore to Los Angeles.
The NCIS team searches for Sam's former partner, Ruiz, who disappears during an undercover operation to buy a deadly explosive.
After a former Department of Defense employee reveals government secrets to a cult, The Church of the Unlocked Mind, Kensi and Deeks go undercover in order to protect him. Meanwhile, the team must prevent the church from selling the secrets to a Chinese spy.
The team searches for Jada (Ella Thomas), the woman Sam led to asylum in the United States four years ago, after she goes missing. Also, Kensi goes undercover with DEA Agent Talia Del Campo (Mercedes Mason).
The team searches for a missing teenage girl who is feared to have been recruited by a terrorist organization,.
Deeks is arrested and interrogated in connection with the murder of his former partner, while the team tries to prove his innocence.
When a suspected North Korean spy is poisoned and hit by a truck carrying Christmas trees, the team must search for who is responsible for smuggling spies into the country. Also, Deeks and Kensi try to find a way to include their mothers in their Christmas plans, and Hetty notices that Granger isn't feeling the holiday cheer.
Kensi and Deeks go undercover at a decommissioned nuclear power plant as the team investigates the radiation poisoning of a Gunnery Sergeant moonlighting as a security guard there.
The team investigates the murder of tech entrepreneur turned venture capitalist who secretly developed a daemon, a background computer program that allows for undetectable data collection.
When Kensi and Deeks announce to the team they are moving in together, coincidentally, Hetty assigns them to protection detail for Jack, Kensi's ex-fiancé, who is in possession of a list containing important contacts in Afghanistan that people are willing to kill to get their hands on.
In order to locate Arkady in Russia, the NCIS team goes undercover with his daughter, Anna, at a gala in Los Angeles to gain access to the Russian Consul General's computer.
While they're in Russia, Callen, Sam and Anna craft a plan to break Anna's father and his CIA agent companion out of prison. Also, Special Agent G. Callen finally learns what the "G" in his name stands for, and in Los Angeles, Kensi and Deeks take Eric into the field on an assignment.
After extensive surveillance footage of Sam's family is found in Africa, Sam and Callen fly there to determine who is responsible and for what purpose. Also, Sam's family is moved from their home to a safe house.
When a convicted Cuban spy escapes U.S. custody just before he is set to return to his country in a prisoner exchange, the team is shocked to learn that Anna helped him break out. Also, Deeks admits to Kensi that he thinks she is too messy.
Callen and the team try to save a child in imminent danger who has been brainwashed by a terrorist cell. Also, Deeks and Kensi discuss having children.
While assigned to protective details for the commander of the Pacific Command, the team searches for a North Korean spy.
After Operational Psychologist Nate Getz fails to check in with Hetty while working undercover on a mission linking organized crime to terrorism, the team learns he is working with an infamous crime leader,.
As Granger escorts Jennifer Kim back to Los Angeles, he interrogates her regarding a North Korean spy and she admits to knowing he is her father.
After some secret information about suspected terrorists disappears from a secure Department of Defense container at the site of a fire, Sam and Callen need to work under cover to investigate.
When Sam receives a distress code from his son Aiden that his school has been taken over by an extremist group, Sam, Callen, Kensi and Deeks rush to San Francisco to protect Aiden and free the hostages.