The young illustrator Song Siyuan had to leave S city where he had lived for a long time due to the death of his parents. This summer, he took a little inheritance from his parents and moved to the countryside - his hometown of Pingshui Town. The strange thing is that he experienced a series of strange supernatural events in the countryside, and then he found that he had entered a different fairy world.
Due to his arrival, a human-demon contract formed in the Song Dynasty was triggered, which led to the rampage of Xuexiu, the demon spirit of Ruoye, and broke the original balance of the cave. When he took over the small wolf-hair pen from his grandfather's hand that could travel freely through time and space, he finally understood the special nature of his family. So he followed Xiaobi's fairy Zhu Xia, his friend Xu Cheng who he had just met, and a group of demons and immortals in Ruoye Cave, traveling through the Six Dynasties, across Kyushu, and clearing the fog of history. While constantly traveling through time, he gradually discovered that Xuexiu's bloody rampage seemed to be related to a past event in the Tang Dynasty.
