Pei Ju comes from a family of ghost slayers. To save his grandfather, whose health is deteriorating after suppressing the monster known as the Mountain Lord, he is forced to inherit a contract and become the new Temple Priest—a living servant controlled by the Mountain Lord. With the help of Han Yitong, an instructor at the Secret Society, and his classmate Ye Youruo, Pei Ju undergoes a series of trials in both the real world and the spiritual realm. Gradually, he uncovers the truth behind his father's death and foils a conspiracy between foreign forces and the Mountain Lord, who have joined forces from within and without. Ultimately, during a decisive battle, his grandfather, Pei Siye, sacrifices himself. When the Mountain Lord attempts to possess Pei Ju, he turns the tables and devours the monster's power instead, becoming the new Mountain Lord.