In the distant past, the "Heavenly Scar" appeared, bringing calamity to humanity. The young demoness Shangguan Zi Yan and the Taoist priest Yuan Chu are intertwined in fate, embarking on a journey to mend the heavens as ninth-rank demon hunters. Shangguan Zi Yan suffers from a malevolent disease, experiencing eccentricities between her body and spirit. At the same time, Yuan Chu is trapped in a love tribulation, where his lover is dying in the process. Having witnessed the full spectrum of human and demonic nature, the two ultimately weave a tapestry of love to mend the heavens and save the world.