In Longyun Town in the early years of the Republic of China, it is said that after the town discovered a treasure, strange things gradually occurred and young girls were killed in their homes one after another. Under the pressure of the mayor, Captain Lin (played by Pang Jingfeng) of the patrol team decides to team up with Ji Lianying (played by Qian Xiaohao), a "righteous man in the rivers and lakes", and a death row inmate in order to find the real murderer and guard Longyun Town.

The film tells the story of narcotics police officer Huang Mingjin and the "mysterious figure" Wei Yunzhou. Through completely different means and methods, in the process of calculating and wrestling with each other, they tear apart the facade of urban tranquility, exposing the underground drug network woven by the hidden hand "Long Wang", and ultimately eradicate the darkness with the sword of justice, revealing the dawn of light.