Infernal Affairs (2002)

In 1991, Hong Kong gangster triad member Liu Jianming (Andy Lau) followed the instructions of the boss Han Chen (Eric Tsang) and joined the police force as an undercover gang. Han Chen promised that Liu Jianming would help him be promoted to a trainee inspector in seven years. In 1992, Chen Yongren (Tony Leung), an outstanding student at the police training school, was...