On the evening of April 28, 2001, a gun case broke out at the entrance of Fanguang Hutong, which is adjacent to the downtown area of Hengzhou City. Xu Guoqing (played by Shi Zhaoqi), the deputy director of the Municipal Public Security Bureau in charge of criminal investigation, rushed to the scene after receiving the report. During the investigation, the police found that the victim Wu Tian had an extremely complicated background and had deep grievances with many people. After analyzing the case, Xu Guoqing had a hunch that this was a vendetta involving grievances between gangs of underworld forces. The police launched a comprehensive pursuit and arrested a group of black gang members who were rampant in Hengzhou according to the grievances of the rivers and lakes, but none of them were the killers behind the "4.28" gun case. At the same time, Liu Huaqiang (played by Sun Honglei), the creator of the "4.28" gun case, was stepping up his planning and implementation of his evil plan. Li Li (played by Jiang Shan), the boss of a real estate company in Hengzhou City, was terrified when she heard the news that Wu Tian was killed, and asked Liu Huaqiang to meet. For the safety of her sister Li Mei (played by Liu Weiwei), Li Li proposed to take Li Mei away, but was rejected by Li Mei. When the police investigation was at a loss, Liu Huaqiang set his evil sights on the next target. The pursuit and counter-pursuit, revenge and prevention of revenge between the police and the criminals began.