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. The three main characters of this drama pose the question of what a ?righteous life? is in the era of political and social turmoil of the late Joseon Dynasty, when progressive thinking and the Confucian social reform movement ?Silhak? began penetrating into Joseon from the Qing Dynasty. It was also a period when the 400-year Joseon Dynasty was gradually losing ground, unable to respond to external and internal changes in the wake of the Japanese invasion of the 16th century and the Manchu War, resulting in clashes between the king, who dreamed of restoring his authority through powerful reforms aimed at improving the lives of grass-root people, and conservative political forces, which felt threatened by the self-justified royal authority.