Storyline:

On the banks of the Tong River in Haizhou City, new clues to the "8/17 Case" from five years ago surface. Zhou Jin, an investigator from the Nancheng Public Security Sub-Bureau, whose elder brother Zhou Chuan is one of the two SWAT police officers who died in the case, volunteers to participate in the investigation. With the help of Professor Jiang Han Sheng, an expert in criminal psychology, the police identify a criminal group led by the mysterious Old Scorpion.