In the mystical Taihang Mountains, where magic flows and powerful yao roam, Hongjun has grown up sheltered from the human world. A half-yao himself, he’s never had reason to leave—until the mountain’s ruler sends him on a dangerous mission: hide his true nature and join the Great Tang Department of Demonic Exorcism in Chang’an. Upon arriving in the bustling capital, Hongjun meets Li Jinglong, a luckless soldier with no spiritual power tasked with leading a team of extraordinary exorcists. Together, they and their enigmatic companions must face the dark forces threatening the city. But as a bond begins to bloom between Hongjun and Li Jinglong, Hongjun wonders: Can he trust Li Jinglong with the truth of who—and what—he is?

Although the Department of Exorcism has successfully thwarted the fox yao’s attempts to infiltrate the imperial examinations, Hongjun, Li Jinglong, and their companions are no closer to uncovering the identity of the yao king of Chang’an. Investigations stall until the group stumbles across a series of bloody murders in the capital. What appears to be a gruesome coincidence soon points to a larger plot as Hongjun and Li Jinglong discover evidence of yao involvement. Yet as the clues pile up, the group fears their enemies’ goals go far beyond murder: They may have their sights set on the emperor himself. Hongjun and Li Jinglong’s growing bond is tested as the fate of the empire—and their very lives—are put on the line in the hunt for the mastermind lurking in the city’s shadows.

GUARDIAN OF DREAMS With the help of Mergen, Hongjun and Li Jinglong have successfully roused the ghost king from his waking dream—but the danger is not yet over. The group soon learns that the one responsible for entrapping the ghost king is none other than the white deer Mergen seeks, a god of dreams who has fallen under the sway of the mysterious yao king. Worse still, the yao king has used the deer’s power to take control of the ghost king’s army, and more undead soldiers are on the way. Before they can formulate a plan, Lu Xu, the fleet-footed scout Mergen rescued on the northern border, sets off alone in the snow. When Hongjun goes after him, he too finds himself snared in a nightmare of the enemy’s making—a vision of his own forgotten past that will upend everything he thought he knew about himself, his parents, and even Li Jinglong.

THE DEMONIC AND THE DIVINE After returning at long last to Chang’an, the exorcists brace for An Lushan’s attack on the city. Li Jinglong lies injured and unconscious, his heart lamp lost, while the six artifacts of Acalanatha have yet to be recovered. As Hongjun and his companions scramble to evacuate the emperor and citizens from the besieged city, it seems no one has the power to stop An Lushan’s monstrous army of demonic soldiers. Everything hinges on Li Jinglong. If he can’t reawaken the heart lamp before it’s too late, Hongjun will have no choice but to counter An Lushan by becoming the heavenly demon Mara, absorbing all suffering of the mortal world into himself. If Li Jinglong still hopes to save Hongjun from his dark fate, he must return to the beginning of everything—and seek salvation in the forgotten depths of their past.