The director of the Public Security Bureau of Haizhou City was shot and fell into a coma. Tian Feng, the former director of the Criminal Investigation Department of the Provincial Public Security Department, was ordered to airborne Haizhou as the acting director. With the cooperation of Deputy Director Hu Kejian and Criminal Police Captain Zhao Mengnan, a comprehensive investigation of the Ran Jiang case was launched. At this time, the mysterious killer appeared in the hospital again and tried to approach Ran Jiang. In the process of investigating the killer, another well-known entrepreneur was killed. Du Dahao, the foreman of two black-related KTVs, came into the police's sight and became the biggest suspect. At the same time, several major anti-gang operations also failed due to leaks. There were undercover gangsters lurking inside the police station, and the police also received important tips from the gangsters. An investigation of undercover and anti-undercover was launched in the police station and the gang. Who is the undercover? Where will the battle between black and white, the battle between good and evil go?