After returning from the north, the Department of Exorcism is no sooner reunited in Chang'an than a series of strange cases strikes the capital. Vicious ghosts have appeared in the imperial mausoleums, slaughtering the guards who protect the remains of former emperors. Whether the attacks are a true haunting, the yao king at work, or the plot of a sinister new enemy, the exorcists must discover the truth before another catastrophe befalls the nation.

Meanwhile, although Hongjun and Li Jinglong have taken a step forward in their relationship, Hongjun continues to be plagued by anxieties. One entity may be able to answer his questions: the divine kun, a powerful yao with the ability to see the future. But the kun is missing, and the yao king--or his agents--may hold the only clues to his mysterious disappearance.