Infernal Affairs is a 2002 Hong Kong crime-thriller film directed by Andrew Lau and Alan Mak. It tells the story of a police officer who infiltrates the crime gang, and a police mole secretly working for the same gang. The Chinese title means "the non-stop path", 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. Due to its commercial and critical success, Infernal Affairs was followed by a prequel, Infernal Affairs II, and a sequel, Infernal Affairs III, both released in 2003.
Pre-release publicity for Infernal Affairs focused on its star-studded cast (Andy Lau, Tony Leung, Anthony Wong, Eric Tsang, Kelly Chen and Sammi Cheng), but it later received critical acclaim for its original plot and its concise and swift storytelling style. The film did exceptionally well in Hong Kong, where it was considered "a box office miracle" and heralded as a revival of Hong Kong cinema which at the time was considered to be direly lacking in creativity.
Miramax Films acquired the United States distribution rights of this film and gave it a limited US theatrical release in 2004.
The Infernal Affairs series was then remade by Martin Scorsese in 2006 as The Departed, starring Matt Damon, Leonardo DiCaprio, Jack Nicholson and Mark Wahlberg. It went on to receive four Academy Awards, including Best Picture, a Best Director win for Scorsese and Best Adapted Screenplay for William Monahan at the 79th Academy Awards becoming the only remake of a foreign film to win Best Picture award.