The exploits of the Los Angeles–based Office of Special Projects (OSP), an elite division of the Naval Criminal Investigative Service that specializes in undercover assignments.
When a Russian bomber goes missing while flying over U.S. soil, Callen and Sam must track it down in the desert and secure its weapons and intel before the Russians on board destroy the plane. Meanwhile, Hetty gives Nell a cryptic assignment.
As the trial begins of a Chief Petty Officer who Callen and Sam arrested for war crimes last year, the NCIS team is called to help find the missing star witness.
When Nell sends Sam to meet an informant who plans to blow the whistle on a military secret, Hanna's life is in danger when the man tries to run him down and kill him. Also, Kensi and Deeks debate whether or not to buy their first house.
The body of a murdered Navy reservist is found by thieves in the midst of a robbery and NCIS must work with the burglars to find the killer. Also, Kensi and Deeks struggle to decide if they are ready to make the leap and buy a house.
In order to get intel on a matter of national security, Kensi must come face-to-face with a sociopath who has been obsessed with her since she put him in jail years ago. Also, though Deeks is desperate to keep Kensi safe, he is forced to leave NCIS.
Before Christmas, Hetty assigns Callen the case of his former foster brother and his wife who, upon reentry into the U.S., are framed for smuggling drugs across the border in her oxygen tanks. Also, Deeks is struggling with losing his job at NCIS.
The NCIS team's murder investigation of a man who sold military information leads to the abduction of a doctor whose cutting edge neurotechnology could be developed into advanced weaponry. Team members are interviewed by FLETC to see if Deeks would make a good NCIS agent. Callen tries to have an important talk with Arkady.
When NCIS investigates the murder of a man about to reveal the source of a massive counterfeiting operation, an old acquaintance becomes their prime suspect and reveals the true reason for her return. Also, Deeks struggles during training to become an official NCIS agent
While NCIS must track down an organized crime leader who is trying to buy stolen defense technology, Callen goes to Anna to ask the ultimate question. Also, Deeks is kicked out of NCIS training only to find that Hetty has a life-changing surprise for him.
When Sam’s daughter Kam is kidnapped after leading citywide protests he will stop at nothing to find her. Also Deeks rejoins NCIS and Callen searches for answers about Anna
When Callen goes to the National Counterterrorism Center on the pretext of interrogating a Russian asset from the crashed plane case he investigated months earlier, the tables are turned and he is detained, accused of being a Russian agent.
After Callen receives a cryptic message from Hetty, he tracks down the person tailing him, bringing him to a remote location teeming with Russians… and face to face with Anna.