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 a triad, and a police officer secretly working for the same gang. The Chinese title means "The Unceasing Path", a reference to Avici, the lowest level of hell in Buddhism, where one endures suffering incessantly. 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 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.