The main line is Zhao Jianguo's investigation of the old "9·12" case in which he was transferred. The "9·12" case was a seemingly ordinary accidental death of a wealthy businessman, but Zhao Jianguo discovered many doubts during the investigation and believed that it was a homicide and related to the "Shadow Society". During the investigation, he continued to encounter obstacles and dangers. At the same time, new cases occurred one after another, and they were all inextricably linked to the old "9.12" Cases. In the process of cracking the new cases, Zhao Jianguo gradually got closer to the truth of the old "9.12" Cases and unveiled the mystery of the "Shadow Society".
