Two chess masters are entangled in several murder cases related to organ transplants. A cop and criminal psychologist Calvin Che have to work together to find the missing link, whilst facing various dangers.

A year ago, Yan Chixia, alongside her family, killed the Fox Demon. Her younger sister Jiang Xue, however, was turned into a demon l, and under the intervention of the sect, becomes even more involved with Yan. The deep misunderstanding brought on by Chixia causes that he has become her mortal enemy. The two are separated by two generations of enmity against the monsters. Yan Chixia becomes one who exterminates demons, while Jiang Xue quietly transforms into a nine-tailed fox known as Shen Si Rou.