Fifty years ago, a magical island known as Horai existed where demons and humans lived in peace. Demons from the outside world broke the peace and left the island shattered.

Now, the island has reappeared after fifty years and draws Inuyasha, Sesshomaru and Kikyo into its midst. With mysterious marks appearing on both Inuyasha and Sesshomaru's backs, the brothers return to the island to discover its secrets.

Little do they know, the return of the island has brought on the attack of the Shitoshin, four gods with their eyes on powers that sustain and protect Horai.

Along with Inuyasha and Sesshomaru, these other han'yō children have the mysterious scars on their backs. To get the scars off they have to destroy the four bosses, who are the Shitōshin alone and combined.