Better than your usual Pang Brothers film, which means it's actually not bad at all. Effective style, a decent story, and a good performance from Aaron Kwok make this a solid commercial film. Much better than either Forest of Death or The Messengers.

Tam is an impoverished private detective. One day, a guy nicknamed 'Fatty' asks Tam to track down a woman who had wanted to kill him. He leaves Tam a portrait of the woman without giving any details. Tam cannot resist the money and starts the investigation. He identifies the woman as Sum, a frequent mahjong player. Tam starts tracking her whereabouts through her mahjong playmates, but he is shocked to find each of them murdered every time he is about to get in touch with them. He discovers a half-burned photo at one of the murder scenes. Tam decides that he has to protect the next target of the invisible murderer. The photo is the only clue for Tam to uncover the case.