Along an empty road in the rural countryside, Wei Wuxian and Lan Wangji stumble across a stone plaque that reads "Yi City." Still on their quest to unravel the mystery behind the cursed severed arm, they venture into the deserted city to obtain further leads.

However, with the appearance of a mysterious new cultivator, the demonic arm investigation leads Wei Wuxian and Lan Wangji to a plot that threatens the cultivation world as they know it. The gravity of the new situation escalates when the two find it involves the chief cultivator of the renowned Lanling Jin Sect—Jin Guangyao.

As the pair continue to piece together the crucial conspiracies of the cultivation history, their friends and colleagues grow suspicious of their motives. With the world against him, Wei Wuxian must prove he is not the demonic sorcerer people believe him to be to regain their trust and save the cultivation world from the sinister evil lurking within it.