In the early days of the founding of the People's Republic of China, prostitution, pimping and drug trafficking were rampant in Nanjing City. In order to straighten out the city as soon as possible, Zhou Longshan, the first director of the Municipal Public Security Bureau, together with a large number of public security officers, spent many sleepless nights. Zhou sent an investigator named Sun Dingyu to investigate an armed drug trafficking gang that had transferred to the water route. The boss of the money shop involved in drug trafficking died while escaping, his brother-in-law Ding Jiaxian continued to commit crimes by evading public security officers. Sun tracked down to the underground drug warehouse in Ding's villa, was discovered, and unfortunately sacrificed. According to the clues already known, Zhou made detailed and meticulous arrangements. After leading everyone to achieve fundamental victory in social security rectification, Zhou received a transfer order and embarked on the journey north.