A few years after the Anshi Rebellion, Tang dynasty military commander Gao Shi suffers a defeat in a battle threatening Chang'an. Trapped in the besieged city, he recalls his lifelong friendship with the acclaimed poet Li Bai.

When an attack shatters the fragile peace between the spirit world and humanity, Hei teams up with Luye, the last disciple of his Shifu Wuxian, to expose a conspiracy that threatens both realms - and the bond they've sworn to protect.