Undercover cop Yan (Leung) has infiltrated the Hong Kong Triads, but a Triad mole in the police department, Ming (Lau), has inturn smoked him out. However, both cop and criminal want the same thing: to be free of their thankless jobs.
This Hong Kong hit thriller plays like a cross between the films of John Woo and Wong Kar-Wai: Woo-style bullet ballets are infused with emotional weight via the kind of attention to the inner state of the protagonist associated with the films of Wong. That wonderful Woo juxtaposition between hero and villain is complicated not merely by Yan (Tony Leung) and Ming (Andy Lau) being on opposite sides of the law, but more dramatically by the fact that both men want to be free from the thankless roles forced upon them.
Yan, who was recruited by the Triads even before he graduated from police academy, has taken to his fake criminal identity too well and, as a result, is undergoing mandatory psychological counselling. Meanwhile Ming, who has been tipping off the Triads to cop activity for ten years, has been promoted to inspector in internal affairs, where he is assigned to smoke out the triad mole - ie himself.
Complexity of relationships aside, Infernal Affairs benefits from terrifically energised camerawork - obvious, really, when you consider co-director Andrew Lau is a seasoned cinematographer who has worked with Wong Kar-Wai, and here recruits Wong's right-hand man, Christopher Doyle, as 'visual consultant'.
With gloss as well as depth, this super-stylish Asian crime thriller should play beyond UK arthouses to become more than another cult favourite.