Infernal Affairs (2002)

Cast: Andy Lau, Tony Leung Chiu-wai, Anthony Wong Chau-Sang, Eric Tsang Chi-Wai, Kelly Chen, Sammi Cheng Sau-Man, Elva Hsiao, Chapman To Man-Chat, Gordon Lam Ka-Tung, Shawn Yue

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, C…