"Infernal Affairs" is a Hong Kong crime thriller film released in 2002. It follows the story of an undercover cop, Chan Wing-yan, who infiltrates a triad organization led by Sam. Simultaneously, a mole within the police force, Lau Kin-ming, works for the same triad. The film explores themes of loyalty, betrayal, and the moral complexities of their dual lives. The narrative builds tension as both characters attempt to uncover each other's identities while maintaining their own cover. "Infernal Affairs" received critical acclaim and won several awards, leading to a successful American remake titled The Departed in 2006.