The prequel to Andrew Lau and Alan Mak's smash hit Infernal Affairs opens in 1991, with Inspector Wong (Anthony Wong) explaining the frustrations of police work to gangster Sam (Eric Tsang). He also expresses his desire to see the seemingly reasonable Sam take over he reins of the local triad from the current boss. When that boss is murdered, with no apparent heir, it seems that Hong Kong is going to explode in an all-out gang war. But the boss' bespectacled, soft-spoken, and well-mannered son, Hau (Francis Ng), unexpectedly takes charge, calmly and cleverly defusing the situation. Meanwhile, Yan (Shawn Yu, reprising his role as the younger version of Tony Leung's character in the first Infernal Affairs) is thrown out of the police academy for breaking the rules, and it's discovered that he's Hau's half-brother. Wong recruits him to work undercover in Hau's organization. Ming (Edison Chen playing the younger Andy Lau) is a corrupt cop secretly working for Sam. His progress up the ranks of the police force is swift, but his relationship with Sam is threatened when he finds himself falling in love with Sam's girlfriend, Mary (Carina Lau). For his part, as the handover of Hong Kong to China approaches, Hau plots to become involved in "legitimate" politics, and to avenge himself against those he believes responsible for his father's death. Chapman To reprises his role as the goofy Keung. Infernal Affairs II was selected by the Film Society of Lincoln Center for inclusion in the 2004 New York Film Festival.