While strange rumors about their ill King grip a kingdom, the crown prince becomes their only hope against a mysterious plague overtaking the land.

Set in Korea's medieval Joseon period, it tells the story of Crown Prince Lee Chang (Ju Ji-hoon), who becomes embroiled in a coup/political conspiracy and is forced to embark upon a mission to investigate the spread of a mysterious undead plague that has beset the current emperor and the country's southern provinces.