Everything seems to have returned to normal – Chan can revert to his true identity as a cop, while Lau has erased his criminal connections by eliminating the triad. The plan succeeds and many of Hon's men are arrested, while Lau betrays and kills Hon. Lau retrieves Wong's cell phone and contacts Chan both of them agree to foil a drug deal by Hon. When the news report that Keung is actually an undercover cop, Hon assumes that he was the spy and that Chan killed him to protect himself. Keung, not knowing that Chan is the mole, drives them away from the scene but dies from a gunshot wound later. Just then, the police show up and a shootout ensues. Chan escapes from the building while Wong tries to distract the gangsters and ends up being thrown off the roof to his death. However, Hon, who knows about the meeting from Lau, sends "Crazy" Keung and other henchmen to confront them. By this time, both Chan and Lau are struggling with their double identities – Chan starts losing faith in himself as a cop after being a gangster for ten years Lau becomes more accustomed to the life of a police officer and wants to end his association with the triad.Īt their next meeting on a rooftop, Wong wants to pull Chan out of undercover work for fear of his safety. Chan nearly finds out Lau's identity when he tries to follow Lau after seeing him talking to Hon in a cinema Lau manages to get away before Chan could see his face.
After this incident, both Wong and Hon realise that they have a spy within their own organisation, placing them in a race against time to find out who the spy is. However, Lau alerts Hon, giving him enough time to get his henchmen to dispose of the evidence.
Wong and his team interrupt a deal between Hon and a Thai cocaine dealer after receiving a tip-off from Chan. Over the course of ten years, Chan experiences great stress from his undercover work while Lau quickly rises through the ranks in the police force, eventually becoming a Senior Inspector. In reality, Chan has secretly become an undercover cop reporting only to Superintendent Wong Chi-shing, who sends him to infiltrate Hon's triad. Around the same time, Chan Wing-Yan, a young police cadet, is seemingly expelled from the police academy. Hon Sam, a Triad boss, sends Lau Kin-ming, a young gangster, to the police academy to serve as his spy in the Hong Kong Police Force.
It is the first in the Infernal Affairs series and is followed by Infernal Affairs II and Infernal Affairs III.
The film follows an undercover Hong Kong Police Force officer who infiltrates a Triad, and another officer who is secretly a spy for the same Triad. Jointly written by Mak and Felix Chong, it stars Andy Lau, Tony Leung, Anthony Wong, Eric Tsang, Sammi Cheng and Kelly Chen. Infernal Affairs is a 2002 Hong Kong action thriller film co-directed by Andrew Lau and Alan Mak.