Nae-gyeong, the most skillful face reader in the Joseon dynasty, was living in seclusion when he was offered a lucrative partnership by Yeon-hong, a gisaeng. Nae-gyeong accepts the proposal to read the faces of Yeon-hong's guests only to get involved in a murder case. With his face reading skills, Nae-gyeong successfully identifies the murderer and his skills are soon acknowledged by King Munjong who orders him to identify the potential traitors who threaten his reign. However, after the unexpected death of Munjong, Nae-gyeong is courted by Grand Prince Suyang who yearns to become King himself by killing the young successor Danjong. Nae-gyeong decides to keep his loyalty to the late King and help Kim Jong-seo protect the young King which forces him into the biggest power struggle in the history of the Joseon dynasty.