Sword in the Moon

The film opens up with an assassination attempt on the king of Joseon at some sort of reception. The attempt is foiled by a special security squad, and specifically by its leader, Gyu-yup. A series of deaths of prominent politicians leads to a nighttime battle in which one member, a female, of what is apparently an assassin duo, is captured. Gyu-yup recognizes this female, and after her torture in prison (of which Gyu-yup is left in charge when she refuses to divulge any information), the film flashes back to Gyu-yup's past.