During the Chin and Han era, Commander Wang Sheng ( Chen Kun) leads his troops in a raid on bandits in the desert, in the process he rescues a beautiful woman and brings her back with them. However he has no idea that this woman, Xiao Wei ( Zhou Xun), is in fact a fox spirit in human form. Xiao Wei needs a regular supply of human hearts to maintain her human form, and the task falls on her helper Xiao Yi ( Qi Yu Wu)--a chameleon who’s also taken on human form and has the special ability to camouflage into the environment he is in. To prove his love and devotion to Xiao Wei, he carries out a spate of murders in order to provide her with human hearts; this terrorizes the whole city.

Meanwhile, Xiao Wei has fallen in love with Wang Sheng, after being impressed with his gallant attempt in rescuing her. She keeps trying to seduce Wang in an effort to steal him from his wife Pei Rong (Vicki Zhao). Pei Rong finds out about Xiao Wei’s feeling for her husband; she also discovers that Xiao Wei is not human, so she secretly approaches martial expert Pang Yong ( Donnie Yen) and demon Catcher Xia Bing ( Sun Li) for help…

Subsequently a drama unfolds that delves into intricate emotions and relationships between man and demon, love and passion, loyalty and temptation, treachery and integrity, ending in a finale with surprising twist.