one of the better in this genre that i've seen. I liked "Running out of Time" but I think this one might even be better, the story was a bit more complex, the game between Andy and Tony to reveal who the undercover is. I watched the mandarin dubbed version, so I don't know if the ending is different then the cantonese version, but this one ended pretty well (not necessarily 'happily'... but you wouldn't expect a happy ending out of this kind of film).

Definitely worth seeing. Filmed very well, good production values too.