A very solid Hong Kong police procedural with some mystery elements thrown in to make it a bit more puzzling. Roy Chow is a capable director, and he handles this type of material with grace, but the story does get a little too farfetched in the second half. If that's a dealbreaker, this is probably not the film for you.
Ling is a police detective tracking a serial killer. During his investigation he is seriously injured, leaving with severe short-term memory loss. Ling tries to pick up the trace again, but he feels he can't trust himself anymore. He does stumble upon some new leads, but they seem so implausible that he's losing the trust of the people around him.
The cinematography looks slick, Kwok and Ho are seasoned actors and the pacing is perfect, even though the film isn't exactly short. The result is typical Hong Kong genre fare, confidently built to be as entertaining as possible, but with a little extra edge. A fun watch, now that Hong Kong's output is just a fraction of what it used to be.