"Infernal Affairs II" is a 2003 Hong Kong crime thriller and a prequel to the acclaimed film Infernal Affairs. Directed by Andrew Lau and Alan Mak, it explores the backstories of key characters, including Chan Wing-yan and Lau Kin-ming, set in the late 1990s. The film delves into the complex relationships between the police and the Triads, highlighting themes of loyalty and betrayal. The narrative follows Chan, an undercover cop, and Lau, a mole in the police force, as they navigate their dangerous roles. The film received critical acclaim for its storytelling, character development, and performances, further solidifying the franchise's reputation.