Human/were-fox half-breed Choi Kang Chi discovers the truth about his origins and searches for the mystical Gu Family Book, which holds the secret to becoming fully human.

A melodrama epic about the great deal of trouble Choi Kang Chi, born as a half-human-half-mythical-creature (or human werefox half-breed), who goes through in order to become human and a story of Choi Kang Chi's journey of struggling in order to live more like a human than anyone else despite not being able to become human. Choi Kang Chi (Lee Seung Ki) is the son of Gu Wol Ryung (Choi Jin Hyuk), the guardian spirit (werefox) of Jiri Mountain, and Yoon Seo Hwa (Lee Yeon Hee/Yoon Se Ah), his human mother. He was raised by the Park family after having been picked up from the river. Due to customary restrictions of the era he is adopted by manager Choi instead, however Park Moo Sol takes on the role of being Kang Chi's main father figure. Kang Chi is an outspoken character who's full of curiosity. He realizes that he's a half-human-half-beast through a certain incident and starts living his second life. Dam Yeo Wool (Bae Suzy) is a master of martial arts and archery. Yeo Wool is an upright character who really values the Three Bonds and Five Relationships in Confucianism, and becomes an instructor at a martial arts center at a young age.—DramaWiki