While the day belongs to humans, the night belongs to yokai, supernatural creatures that thrive on human fear. Caught between these worlds is Rikuo Nura. He's three-quarters human, but his grandfather is none other than Nurarihyon, the supreme commander of the Nura clan, a powerful yokai consortium. So, Rikuo is an ordinary teenager three-quarters of the time, until his yokai blood awakens. Then Rikuo transforms into the future leader of the Nura clan, leading a hundred demons.
The battle against Nue heats up as Rikuo and members of the opposing clans move to Mt. Osore, a holy mountain where spirits of the dead are called into battle. Will a reforged Nenekirimaru, the renowned yokai-killing blade, work to defeat the legions of the undead?