This film is one of Chow Yun-fat's early hero films. One night, a police officer was accidentally shot and killed while searching the red-light district. The senior police officers realized that there was a group of unusual gangsters hiding here. Assistant Liu contacted the police station's undercover agent who had been deployed in the underworld, and was also his nephew, Gao Qiu (played by Chow Yun-fat), and asked him to get into the gang as soon as possible and learn about their criminal plans. Gao Qiu turned into a gun dealer and got in touch with the bandit leader Nan Ge and his subordinate A Hu (played by Danny Lee). Assistant Liu was afraid that his nephew would have an accident, so he sent someone to follow him secretly. Unexpectedly, Gao Qiu successfully gained the trust of the gang because of the police's tracking. Nan Ge officially pulled Gao Qiu to join their plan to rob the gold shop. In the little contacts with A Hu, Gao Qiu found that he gradually established a brotherhood with him. On one side is brotherhood, and on the other side is social justice. How will Gao Qiu choose?