500 Years ago, Demon King Tantai Jing was born weak and fell into the River of Eternal Life. He was seen by Su Tingting and Huangfu Sang who were visiting here. Su Tingting was unwilling to pay attention to this local demon with no immortal power, and was finally rescued by Huangfu Sang... (The Demon King has feelings, but he is destined to only love one person in his life.) The Demon King gradually developed a liking for her while living with Huangfu Sang. At the same time, the immortal clan has been arresting Huangfu Sang (because the secret that Huangfu Sang is the Fairy Light was discovered by Su Jiyi, and the head of Su needs the power of Fairy Light to become king in the fairy world). Fairy Light also left the Demon King in order to find her true identity. By mistake, Huangfu Sang was sent to Tantai Jing's bed after being drugged (one-night stand)
Huangfu Sang was instigated to kill the Demon King in order to save the Yongsheng River. He found out that Tantai Jing regretted it, but Tantai Jing survived the catastrophe. When he went to Huangfu Sang to ask for information, Tantai Jing and Huangfu Sang accidentally entered the whirlpool of the Yongsheng River. In order to make up for their mistakes, they gave the protective state of mind to Tantai Jing, and they have been reincarnated. Tantai Jing discovered the truth and almost destroyed the fairy world, but was told by Shen Shangjin that she could go to the human world to find Huangfu Sang who had no memory.
After some efforts by Tantai Jing, Huangfu Sang's memory was restored and he became the God of Light. Tantai Jing and Huangfu Sang guard the Yongsheng River together
Intention: to resolve misunderstandings and go both ways