Infernal Affairs (film series)

Infernal Affairs is a series of three crimethriller films directed by Andrew Lau and Alan Mak, starring Andy Lau and Tony Leung. It tells the story of a police officer who infiltrates the triads, and a police officer secretly working for the same gang. The Chinese title means the nonstop way, a reference to Avici, the lowest level of hell in Buddhism. The English title is a word play combining the law enforcement term internal affairs with the adjective infernal.

Infernal Affairs focuses on a police officer named Chan Wingyan Tony Leung, who goes undercover into a triad, and a triad member Lau Kinming Andy Lau, who infiltrates the Hong Kong Police Force. Each mole has been planted by the rival organisation to gain an advantage in intelligence over the other side. The more the moles become involved in their undercover lives, the more issues they have to cope with.The prologue opens with the introduction of triad boss Hon Sam Eric Tsang, who sends a number of young gangsters to the police academy as moles, among whom include a young Lau. Concurrently, a young Chan joins the police force but is seemingly expelled from the academy even though he manages to impress Superintendent Wong Chishing Anthony Wong. In reality, Chan has become an undercover agent reporting only to Wong. Over the course of ten years, Chan experiences great stress from his undercover work while Lau quickly rises through the ranks in the police department. The film begins with a meeting between Chan and Lau in a hifi store without either of them knowing the others identity. ........

Source: Wikipedia