After NCIS fails to locate a mole in the department, Under Secretary of Defense Corbin Duggan insists on new leadership and takes over the Los Angeles unit from Hetty and Granger.

After a Navy reservist is killed while protecting a city councilman, Sam is sent undercover in a private security firm with links to several criminal organizations.

During the murder investigation of a Navy Lieutenant on leave in Los Angeles, the NCIS team uncovers classified surveillance briefs she smuggled into the city that may have been sold to a foreign buyer.

The NCIS team is joined by NCIS Special Agent Nicole DeChamps after a Marine reservist with a history of PTSD disappears following a drunk and disorderly altercation.

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

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.

The NCIS team scrambles to find Kensi, when she is attacked and kidnapped by a mysterious militia group while helping a group of migrants cross the border.

When a civilian scientist working with the marines is killed, and her advanced radar technology stolen, the NCIS team must scramble to find the missing technology and the culprit. Deeks worries about how to tell Callen that he's selling the bar.