When Callen goes rogue and embarks on a secret mission that leaves Sam and the team in the dark, Hetty demands that his operation be shut down and tasks the team with finding him.
When a gunnery sergeant moonlighting as a security guard at a decommissioned nuclear power plant suffers radiation poisoning, the team goes under cover to investigate.
A tech entrepreneur and venture capitalist who secretly developed a computer program that stealthily collects data is murdered.
Kensi and Deeks let everybody know that they are moving in together before they are assigned to protection detail for Kensi's former fiance.
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.
Nate Getz's loyalties are questioned after he fails to make contact with Hetty whilst working under cover to find a link between organized crime and terrorism.
Granger goes with Jennifer Kim to Los Angeles. Jennifer admits to him that she knows 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.