《无间道》, also known as "Infernal Affairs," is a Hong Kong crime thriller film released in 2002. The story revolves around an undercover cop, Lau Kin-ming, who infiltrates a triad organization led by Sam. At the same time, a mole within the police force, Chan Wing-yan, works for the same triad. The film explores themes of loyalty, betrayal, and the blurred lines between good and evil. The movie was directed by Andrew Lau and Alan Mak and received critical acclaim for its gripping narrative and strong performances. It won several awards and was later adapted into a Hollywood film, "The Departed," directed by Martin Scorsese. The success of 《无间道》 has made it a significant work in the crime thriller genre.