The snake demon Bai Suzhen (Ju Jingyi) was enlightened by Guanyin and came to the human world to practice. She met Xu Xian (Yu Menglong), a doctor who practiced medicine in Lin'an City. At the beginning, Bai Suzhen and Xu Xian were swindlers, so they had a competition with him to see who could cure Changsheng's mother's disease first. Soon, Bai Suzhen discovered that Changsheng's mother was poisoned by snake venom. Following this clue, Bai Suzhen met Xiaoqing (Xiao Yan), a green snake spirit who practiced in the human world like herself. The two did not know each other, and finally let go of their previous suspicions and became sisters. Children disappeared one after another in Lin'an City. The monk Fahai (Pei Zitian) discovered that this was caused by the demon, so he set out to Lin'an to catch the demon. Fahai locked his suspicion on Bai Suzhen's Xiaoqing and made things difficult for them. In the end, everyone realized that all the incidents were caused by the centipede spirit. Qingbai and the two assisted Fahai to capture the centipede spirit.