A film credited for single handed reviving the fledging Hong Kong film industry in 2002 Infernal Affairs is set in the never-ending war between the police and the Triads of Hong Kong. Chan is an undercover cop who has managed to infiltrate the Triads while Lau is a Triad member who has infiltrated the police force. Both feed their bosses vital information on the plans of the organizations they pretend to serve. When the presence of a mole is realised by both a cat and mouse game of survival ensues between Chan an Lau. Filled with original twists Infernal Affairs is one of the best police stories ever inspiring countless remakes worldwide.