In recent years there has been no lack of Hong Kong-based crime dramas highly accomplished in their verite use of urban locales and gritty depiction of hard-boiled characters. What distinguishes Derek Yee's edgy nail-biter (2004) is how effortlessly he shifts the tone of his narrative. While it begins as a standard-issue drama focusing on a struggle between two gangs, gradually it transforms into a study of the relationship between a bumpkin from mainland China and a prostitute. Yee's treading familiar territory—the bumpkin's being manipulated by a greedy stolen-goods trafficker turned police informant, and the winsome hooker has a heart of gold. But his nuanced plot and character development make this a rich and disturbing drama. With Daniel Wu and Cecilia Cheung. In Cantonese and Mandarin with subtitles. 109 min.