Hetty goes rogue, leaving the NCIS team completely in the dark, and the mole kidnaps one of the agents.

A gold heist investigation has the NCIS team working with Hetty's former Vietnam War colleagues, Retired Admiral AJ Chegwidden, Admiral Sterling Bridges and Retired Captain Charles Langston.

The team investigates a ransomware attack that takes out the entire power grid for west L.A. and paralyzes the city. Also, as the first holiday season since the death of Sam’s wife approaches, he struggles to find the best way for his family to celebrate.

Deputy Director Ochoa volunteers the NCIS team to assist with a covert operation tied to a terrorist group advocating for extreme military force. Also, Callen has concerns as to what an assignment of this nature could mean for the future of the team.