On the grounds of the US Naval Academy, an Army cadet and a Navy midshipman find an unattended car and the body of a civilian physician, shot to death in an execution style; Gibbs and company investigate. Vance recognizes the MO; he says that someone from his past (17 years before), a North Korean woman assassin, Kai, has come into his jurisdiction and back into his life. Ducky finds a message, and Abby interprets it. Kai calls Vance and teases him. Vance and Gibbs make plans; McGee finds the ride for Kai from Los Angeles. A young lady, Amanda, puts a spring into McGee's step. Someone shoots but does not kill a North Korean official near the Capitol; he later dies. Vance receives a question. Abby says that the same person shot both the physician and the official, and that the shooter added a twist. McGee meets Amanda for coffee, but a question and someone else interfere. Vance goes home and finds a curious triangle, which plays out in a strange way.