The rebellious young hero You Fang accidentally reveals his demon heritage while rescuing his companion Cai Wei, who is investigating a missing girl. Pursued by the sorcerer Xuan Zhen and the new demon king Ogino, You Fang, with help from his master Zhuge Shi Fang and old friend Master Wu Chen, seeks to solve the mystery of the Book of Heaven. Along the way, he teams up with his twin brother Diye to combat ruthless killers and ultimately fights to save the common people..