Posing as a crazed member of the Lanling Jin Clan, Wei Wuxian takes refuge in the Cloud Recesses while his former cultivation classmate, Lan Wangji, investigates the mysterious demonic arm in their possession. With its dark energy radiating ominously, the two are compelled to work together to contain it. However, the demonic arm is not the only dark presence in the area and as spiritual unrest grows in the Gusu Lan Clan's mountains, Wei Wuxian and Lan Wangji must strive to restore balance.

The tale of Wei Wuxian's fall from grace continues as more is revealed about his journey down the path of demonic cultivation. The demonic arm only intensifies his mischievous spirit, making this the time for Wei Wuxian to demonstrate that he has truly forsaken the forbidden path and is no longer the maniacal sorcerer that he once was.