Screening at the 42nd New York Film Festival, Lincoln Center's Alice Tully Hall, October 10, 7 pm.

This griping prequel to Infernal Affairs is set during the 1990s when Hong Kong was turned over to China. Ming (Edison Chen), a young gangster who is working for Sam Hon (Eric Tsang), shoots a powerful godfather (Joe Cheung) and sends waves of anxiety through the ranks of other bosses of the city's underworld, known as the Triads. This man's oldest son, Ngai Wing-hau (Francis Ng), is convinced that he was done in by his four main criminal compatriots in Hong Kong. He vows to take revenge.

Meanwhile, Ming enters the police academy as a trainee, and Yan (Shawn Yue) leaves the academy when his superior, Wong (Anthony Wong), discovers that he's a half-brother to Ngai. Much to his surprise, this young man is tapped to become a stoolie within the Triads. Most of the picture deals with the incredible difficulties both informers have as they struggle to evade exposure. Equally mesmerizing is the theme of the fine line between upholding and breaking the law.

Director Andrew Lau draws out fine performances from Anthony Wong as the exhausted police superintendent and Eric Tsang as the wily and ruthless crime lord. Again the cinematography of Hong Kong is used to convey the shadowy elements of police work. The music by Chan Kwong Wing is perfectly in sync with the tension of the drama.