Infernal Affairs (2002)
Original Title: 無間道
Videos: Trailers, Teasers, Featurettes
Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.
Infernal Affairs - watch online: streaming, buy or rent
Currently you are able to watch "Infernal Affairs" streaming on Netflix.