Long ago, in the land of Lanistra, a demon by the name of Isharul appeared. He lashed out against the world, seeking to destroy everything in sight. Only with the help of Princess Atsuki was the beast dispelled. Yet as he faded, Isharul placed a curse upon the land. And so it was that if a person committed one of the seven deadly sins in a great enough magnitude, they would become possessed by demons themselves. Follow the journey of Kenshi, a wandering demon hunter, and his brother, a demon cat seeking a way to return to his true form. Can they find a way to end the curse and save Lanistra?