Jing Wong and Marco Mak try to cash in on the horror hype. With a plot and setup not unlike Saw they deliver a film that isn't quite sure what it wants to be, drifting between horror and police thriller, with the odd parody element thrown in for good measure (because that's what you get when Jing Wong is spinning the wheels).
A serial killer is on the loose. He targets young models and kidnaps them. The only way they are allowed to escape is by weighing less than 35kg, an almost impossible task. Detective Tak is put on the case, but his job suddenly becomes a lot more pressing when he gets his personal life entangled with the case.
Like most Hong Kong horrors, the film never really commits to the genre, with the comedy bits being more than a little counter-productive. It's good to have Anthony Wong on board, the rest of the cast isn't on the same level. It's certainly not the worst film, but unless you're desperate for horror or you're a true Wong completist there's no good reason to prioritize this one.