Lee Na Young (Kim Ha Eun) was trained to be an assassin after bing rescued from servitude when her high ranking father was convicted of treason. Her childhood sweetheart Park Sang Kyu (Jin Yi Han) who had returned from studying abroad and worked as a government official was looking all over for her. So did her former servant Yang Man Oh (Lee Chun Hee) who had become the leader of the merchant group. The three got entangled in a conspiracy against the Emperor who was determined to carry out reforms to create a new Korea whereby the class system would be eliminated.