Introduction: In the 37th year of Wanli reign of the Ming Dynasty, murders occurred one after another in gunu County, Jiangnan. The dead had different identities and had nothing to do with each other. The bodies were arranged in strange postures. A sentence was left at each scene of the crime. As the apprentice of the first victim, the little Constable Qu Sangen cooperated with his little partner to carry out an investigation. With the deepening of the investigation, people from all walks of life, farmers, businessmen and so on came to the scene. In the fog, an old case ten years ago surfaced. Who is the murderer and what is his purpose?