Under the guise of a madman, Wei Wuxian takes refuge in Cloud Recesses, while Lan Wangji, his former classmate, delves into the mystery of a malevolent severed arm. Together, they grapple with the ominous power emanating from the limb, facing not only this sinister threat but also other dark forces looming in the Gusu Lan Clan's mountains. As tensions escalate and spiritual balance teeters, Wei Wuxian's tainted journey into demonic cultivation unfolds. The burden of the demonic arm tests his resolve, urging him to prove his redemption from the shadows of his past and dispel the lingering perception of him as a malevolent sorcerer.