Infernal Affairs (2002)

Chan Wing Yan, a young police officer, has been sent undercover as a mole in the local mafia. Lau Kin Ming, a young mafia member, infiltrates the police force. Years later, their older counterparts, Chen Wing Yan and Inspector Lau Kin Ming, respectively, race against time to expose the mole within their midst.

Infernal Affairs keeps every mind human — it fights its subject at zero distance. The story fights on E8/E11 of the E0–E14 reality ladder.