A Navy Lieutenant working at the Pentagon's cryptography department is found dead in her home, having seemingly committed suicide by shooting herself in the head. However, Abby later discovers that there was someone else with the Lt. when she died and as such, the team attempt to find her killer while also searching for the mole. When evidence links the Lt. to a Venezuelan diplomat Simon Roca, the team must find a way around the red tape in order to find out what really happened. While they race against time to tie Roca to the Lt., Ducky is held up by his mother, who is suffering from dementia.