Black Hair and White Hair grow up in the Sau Mau Ping ghetto together as brothers, but are torn apart as adults when Black (Anthony Wong) trains to be a cop and White (Michael Tiu) aspires to rise within the ranks in the triads. Black is by no means a perfect cop as he has gambling debts, buys prostitutes and convinces himself this is the way to control the world. A new cop (Edward Mok) attempts to clean up matters efficiently and by the book but soon find themselves involved in a web of revenge, misunderstandings and betrayal.