A martial arts detective story set during Korea's Choson Kingdom. A young female detective Namsoon and her trusty companion Detective Ahn are called to investigate a case involving counterfeit money. She goes undercover and disguises herself in several incarnations: as a man at a tavern, as a woman selling liquor at a colourful marketplace and as a beautiful Kisaeng, the Korean equivalent of a geisha. Namsoon repeatedly encounters a mysterious, handsome swordsman named Sad Eyes and it is sparring at first sight. Evidently and inexplicably attracted to each other, they engage in a cat-and-mouse game and engage in duels that only strengthen their mutual feelings. But their combat also results in the devastating disclosure that Sad Eyes, as a loyal acolyte of the Minister of Defence, has a role in the latter's plot to seize control of the country and is therefore Namsoon's enemy.