During the Qin and Han Dynasties, Commander Wang of the Wang family army saved a beautiful woman named Xiaowei in a fierce battle with sand bandits in the Western Regions and brought her back to the Jiangdu Wang residence. Unbeknownst to him, this Xiaowei was actually the "Nine Skies Beauty Fox" disguised in human skin. Her skin must be maintained with human hearts, so Xiaowei's invisible assistant Xiaoyi —— a demon transformed from a desert lizard —— kills people every few days to offer their hearts to Xiaowei as a sign of his love for her. Consequently, the city of Jiangdu is plunged into terror. Xiaowei also develops feelings for the brave and handsome Wang, and uses her demonic powers to seduce him, aiming to replace the position of Wang's wife, Peirong. Peirong discovers Xiaowei's infatuation with her husband and senses that she is not an ordinary person. Thus, she secretly seeks help from the highly skilled wandering swordsman Pang Yong and Xia Bing, a pure-hearted demon slayer, to save Wang... From here on, a complex web of emotions, temptation, betrayal, resistance, and life-and-death battles between humans and demons unfolds.