A series of serial murders set off a carnival and restlessness in the city. In several cases, the victims were tortured to death, and the scenes were full of rituals. All the clues were related to one person - Fang Mu (played by Deng Chao), a genius detective who is proficient in criminal psychology. While investigating the case with his colleague Mi Nan (played by Liu Shishi), Fang Mu discovered that Jiang Ya (played by Ruan Jingtian), who was once his high school classmate, seemed to have many secrets. At this time, a user named "City Light" appeared on the Internet, initiating a vote to let the public decide the life and death of lawyer Ren Chuan (played by Guo Jingfei). Although Fang Mu, Mi Nan and other police officers tried their best, they still couldn't stop this dark trial of "fighting violence with violence", and the city fell into a vortex of chaos. At the critical moment, Fang Mu realized that Jiang Ya's wife Wei Wei (played by Lin Jiaxin) was actually an important witness to unlock Jiang Ya's secret. Just when the truth was about to come to light, an amazing change suddenly happened...