Duanmu Cui, a fairy from Penglai comes to the mortal world to supervise the evils. She gets acquainted with Zhan Yan, a constable of Qifeng. Although the two get off on the wrong foot, they fall in love when they solve cases together. Cui recalls her past history with Kuchang a thousand years ago before she falls into the abyss where she loses her memory, is given a new identity and implicated in a conspiracy. Zhan Yan vows to act against the will of Heaven to bring her back.