Long before Rikuo Nura was born, the legendary youkai Nurarihyon, leader of a "Night Parade of One Hundred Demons," fell in love with a human woman. Though the two would initially find happiness, a threat from the terrifying fox-demon Hagoromo Gitsune would get in the way of their relationship.

In the present, Rikuo has taken his rightful place as the heir to the Nura Clan. While he has accepted his youkai side, he must continue to maintain the secret of youkai, a difficult task when faced with the Keikain onmyouji clan and his youkai-obsessed friend, Kiyotsugu. Even so, Rikuo will do what he must to protect those important to him.

The reappearance of the sinister Hagoromo Gitsune marks the start of Rikuo's most fearsome trial yet. The frightening creature bears a personal vendetta against his family and will stop at nothing to see her dream come to fruition. The world stands at a precipice, an all-out war that will drag Rikuo centerstage.

Rikuo Nura, a part-youkai and part-human boy, grew up as the young master of the Nura Clan. Comprising youkai of all shapes and sizes, Rikuo treated the clan like family, however, he learned that he was the only one among his classmates who saw them in this light. To most, they were terrifying creatures of folklore who ate children and relished in bloodshed. Taking this to heart, he swore to live his life as a normal human.

Normalcy, however, is hard to come by for young Rikuo. Complicating his goal are his youkai attendant, who under the name Tsurara Oikawa, goes to school alongside him; the young onmyouji Yura Keikain; and his close friend Kiyotsugu, who idolizes youkai and hopes to prove their existence. To make matters worse, rival youkai and other entities threaten to harm those Rikuo holds dear.

If he wants to protect what's important to him, Rikuo must acknowledge his ancestry—that he is the grandson of the legendary Nurarihyon—and transform at night into a youkai, becoming worthy of being the next leader of the Nura Clan.