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.