This is a neat thriller from Hong Kong. Considerably more arty than the venerable shoot-em-ups we used to see from John Woo. The action follows an undercover cop posing as a trusted underling for "Sam", a devout Buddhist gangster. But Sam has also placed a mole in the Hong Kong police department. And (as fate would have it), the two spies wind up playing a cat-and-mouse game, each trying to discover the other's identity without revealing himself. Both protagonists have the usual psychological stress common to undercover operatives in Hong Kong movies.
Two notes for would-be viewers: (1) You can watch the movie dubbed into English, or you can have English subtitles, or both. But don't do both, because they conflict sometimes and this can be jarring. (2) The hot Asian chick seen on the DVD case with the skimpy blue dress, boots, and big gun does not actually appear in the movie. I looked really hard. So caveat rentor.