An undercover cop goes deep undercover to inside one of Hong Kong's most notorious Triad gangs only to find him getting consumed by a life of crime and seediness.

Inspectors Tong (Shaw Brothers regular Pai Ying) and Cheng (Kent Cheng) are investing a psychopathic serial killer who has been raping and murdering prostitutes. With the help of a young prostitute, they follow the bloody trail to...