Bumbling private detective Chan Tam is enlisted by police pal Fung Chak to help in the investigation of a serial murder case. The victims a middle-aged man killed at home, a dead woman found in the trash dump, and a teenage girl slain in the park were all killed in grisly manners, but they didn't seem related to one another. With no clue to follow up on, Tam is decidedly at his wits' end.
Chen Tan, a private detective in Thailand, travels to Malaysia following a series of clues found in a photo. There he searches for a man called Chai, who might help reveal the truths behind the murder of his parents 30 years ago. Chen finds Zheng, a Malaysian detective born in China. Together they meet Chai's daughter, Zi-Wei who could hold the key to cracking the case.
When a bloodied and incoherent Jun (Wang Baoqiang) confesses to five murders that have not occurred, the police assume that he's mentally unstable and ignore his claims. Police detective Han (Lau Ching-wan) is investigating a series of gruesome murders, but soon discovers that all is not as it seems and that not only are the murders connected, but that Jun is tied to them in some way.
