Policeman Zhang Dahai (played by Lian Kai) drove the prisoner Situ Qi (played by Lam Ka Tung) back to the police station, but encountered an accident on the way and accidentally broke into the Walled City. The Walled City is full of lawless people from all over the country. They set up camp here, operate and maintain their own laws. It is a typical "no man's land". The leader of the Walled City, Crow, detained Zhang Dahai and Situ Qi and threatened to kill the one who was a policeman. At this time, the brothel madam A Ling (played by Tian Ruini) stood up and framed Situ Qi as a policeman, which allowed Zhang Dahai to gain freedom. It turned out that Situ Qi and Zhang Dahai were once lovers, and they also had a daughter, A'en, but later Situ Qi abandoned the mother and daughter and disappeared. A Ling hoped that Situ Qi could help them leave the Walled City and protect A'en from the crows.