A group of demons in the ancient Japanese capital of Heian is dismembering members of a family of Japanese nobles.

During a dark time in the Heian period, when evil forces threaten the kingdom, the emperor relies on the onmyōji to keep the supernatural forces in line. But as political events become highly charged, friction within the order leads to betrayal. Now, Seimei, a talented member of the clan, must face down his master, Dōson, in the hopes of restoring peace to the kingdom.