The play is adapted from Teng Luo Weizhi's novel "Black Moonlight Holds the BE Script". In order to save the world ruled and tortured by the demon god Tan Tai Jin (played by Luo Yunxi), Li Susu (played by Bai Lu), the daughter of the head of Hengyang Sect, went back five hundred years ago and transformed into Ye Xiwu, the youngest daughter of the Ye family, to prevent Tan Tai Jin, the hostage of Jingguo, who had not yet been completely eroded by evil thoughts, from becoming a demon god. Unexpectedly, Tan Tai Jin was Ye Xiwu's husband, and the two gradually fell in love. In the end, Li Susu proved the truth with her own body and changed the fate of Tan Tai Jin and the world. After losing his love, Tan Tai Jin searched for Li Susu's soul by the Nether River for five hundred years. He was rescued by the immortal gate when he was on the verge of death. Since then, he has become a disciple of the immortal gate. He changed his ways and met Li Susu again. Just when the two broke the mirror and reunited, Tan Tai Jin's demon fetus body still caused criticism and covetousness, and the three realms were in danger again. Faced with a cruel fate, the two lovers, despite numerous misunderstandings, finally came to terms with each other. One became a god, while the other became a demon. Together, they turned the tide and prevented the world from being destroyed.