Infernal Affairs (2002)

Something fishy is going on in the anti-Drug Trafficking Unit of the HK Police, and only a few honest cops know that the corruption goes all the way to the top. However, they must prove their case quickly, and by unconventional means, after they are framed for murder and drug-trafficking themselves. Dodging bullets from cops and criminals alike, the race is on to clear their names, protect their loved ones, and bring their corrupt colleagues to justice.

Ko Chow is an undercover cop who is under pressure from all sides. His boss, Inspector Lau, wants him to infiltrate a gang of ruthless jewel thieves; his girlfriend wants him to commit to marriage or she will leave Hong Kong with another lover; and he is being pursued by other cops who are unaware that he is a colleague. Chow would rather quit the force, feeling guilty about betraying gang members who have become his friends.

Cheung Sung-bong is a highly respected cop with a long history of success in dangerous cases. However, his past soon comes back to haunt him when a former protégé resurfaces, seeking revenge.

A police inspector becomes obsessed with apprehending a criminal planning a major heist at the Hong Kong Jockey Club in the weeks leading up to Hong Kong's return to China.

Drug lord Dwayne Gittens rules Cincinnati with an iron fist. No wonder he's known as "God" on the streets. Determined to break Gittens' stranglehold on the city is undercover cop Jeffrey Cole. But as Cole takes on an assumed identity to penetrate Gittens' criminal empire, he makes a disturbing discovery -- he kind of likes being a gangster.

Hong Kong's three notorious thieves who have never met one another before appear in the same restaurant. This leads to a rumour that they are joining forces to pull off something big before the Handover, though this is not something that any of them.

Hoping to raise enough capital to finance a legitimate business and leave behind his life of crime, Liverpool underworld boss Ged Brennan sends his brother Ratter and a crew to pull a daring final heist. But when Ratter kills a drug kingpin during the job, Brennan must turn to rival crook Franner to avert an all-out gangland war.

Liu Yue Ping reports to the ICAC about a rich 2G Cao Yuen Yuen who bribed officers of the Hong Kong Correctional Services (HKCS) from inside the prison. William Luk decides to infiltrate the prison as an inmate to conduct his investigation, while his partner Ching Tak Ming and Chief Inspector Lau Po-keung back him up from the outside.

A special agent has for 8 years been deep undercover in Asia's lucrative organized crime trade as he plays protégé to one of the key players, Banker. Now, Nick has but he has started to feel loyalty to his new environment and to the money.

While undercover officer Kit is taken prisoner by the syndicate, he befriends his keeper and discovers an organ trafficking ring.