Cops were shot when searching the red-light district. The policy realized the existence of dangerous gangsters. Inspector Liu asked undercover officer Gao Qiu to spy the gangster. Gao personated an arms dealer and got in touch with lead gangster Nan and his man A-Hu. Liu dogged them to cover his nephew. Gao won the trust of the gangsters. Nan invited Gao to their robbery. Gao got close to A-Hu and found there was a brotherhood between them....