The head of the Tianshi Sect in Qingcheng Mountain, Zui Dao Ren (played by Yuan Xiangren), is a martial arts master who is proficient in magic and is sent to guard the prison. However, due to his drunkenness and negligence, the imprisoned criminal Xie Sheng Zheng (played by Yuan Xinyi) escapes from the Tianshi Sect and endangers the world. In order to practice poison skills, Xie Sheng Zheng eliminates his fellow apprentices and searches for boys and girls born during the time of extreme yin, and practices the Nine Yin Boy Skill, intending to take revenge on the Tianshi Sect. You Baiyun (played by Yuan Richu), the only descendant of a folk Xuanmen family, happens to be a boy of extreme yin. By chance, he meets Zui Dao Ren and fights against Xie Sheng Zheng's conspiracy together...