Two bizarre murder cases have occurred in the small city of Wucheng, Linhai. The peaceful life of the single mother Li Xiulan (played by Zhang Lu) and her daughter Li Yan (played by Xu Mengjie) was broken due to the arrival of the police... As the case continues to deepen, police Qin Yang (played by Lan Haimeng) and others uncover the veil of serial crimes layer by layer, and all clues such as puzzles point to an evil deed buried by time.