Hong Kong police officer Li Zhongzhi (played by Louis Koo) learned that his daughter Zhi (played by Hannah Chan) disappeared inexplicably while traveling in Thailand, so he went to Thailand to call the police for help. The Chinese detective in charge of the case, Cui Jie (played by Wu Yue), agreed to let him investigate together, but Li Zhongzhi used the media to appeal to the public to provide clues. A video clip of Zhi being taken away was accidentally uploaded to the police website, but it was mysteriously deleted. Cui Jie and his friend and colleague Tak (played by Tony Jaa) went to find the owner of the video, but they encountered a mysterious person who intercepted the feet and destroyed the evidence. They met on a narrow road, started chasing and fighting with him. Li Zhongzhi and Cui Jie gradually investigated, but found that there was a case within the case, and began to realize that the mysterious force behind the murderer was not something they could deal with...