Lau and Chan both attended Hong Kong's police academy; Chan is chosen by a senior police officer to go undercover and to infiltrate the Triad gangs, while Lau IS a Triad operative working undercover inside the police force - so, there are two moles, neither one aware of the other's identity, involved in a ruthless battle of wits between the police and the drug-runners.
The screenplay for Infernal Affairs, by Alan Mak and Felix Chong, is a clever one; once you get past the slightly complicated opening scenes and you lock into the plot, you're kept on the edge of your seat by the tense and often unexpected ways in which this superior crime thriller develops.
A huge success in Hong Kong, the film, directed by Andrew Lau and Alan Mak, never puts a foot wrong in the unravelling of its tense, tantalising scenario, and there are terrific lead performances by Tony Leung and Andy Lau as the two men living dangerous double lives. Watch for the Hollywood remake - I understand Brad Pitt's interested.
Watch 'Infernal Affairs'
Sunday 4 April, 8:30pm / Tuesday 6 April, 1:00am on SBS World Movies
Now streaming at SBS On Demand
Hong Kong, 2002
Genre: Drama, Action, Thriller, Crime, Mystery
Language: Chinese, Thai,
Director: Andrew Lau, Alan Mak
Starring: Andy Lau, Tony Leung Chiu-Wai, Anthony Wong, Eric Tsang, Kelly Chen