he head of an elite Hong Kong surveillance unit (Simon Yam) keeps one eye on his rookie apprentice (Kate Tsui) and the other on a notorious criminal (Tony Leung Ka Fai) he suspects of masterminding a recent jewel heist in this tense thriller from filmmaking duo Johnnie To and Nai-Hoi Yau. Of course, the criminal knows all along he's being watched. But that doesn't stop him from trying to pull off the biggest score of his career.

Overview from themoviedb.org