Korea, Joseon era. In the provincial city of Wonju, Yang Myung-jun's father disappears, while conducting an investigation involving the governor. The young man tries to discover what happened to his father with the help of his best friend, Prince Lee Baek-hyeon, and thanks to the information shared by Jeong Jae-eun, a witty noble woman, they start to uncover the truth. However, they have to put an halt to their investigation to help track down a beast that has killed several people in the district, unaware that all these events are linked and that a great danger looms over their heads.