At first glance, Nura Rikuo seems like nothing more than a normal middle-schooler. In actual fact, he is grandson of Nurarihyon, master of a youkai clan. Having only recently resolved the hostilities between the Nura Clan and the Shikoku Yokai, Rikuo finds no rest as an ancient enemy of the Nura Clan, Haguromo-Gitsune, resurfaces. After 400 years of inactivity, Haguromo-Gitsune suddenly sweeps through Kyoto with overwhelming power.

[Source: AniDB]