Ritsuka Aoyagi has just transferred to a new school soon after the gruesome death of his brother Seimei. Upon entering school, he is branded as a weirdo and is aloof toward the other students. When Ritsuka discovers a posthumous message from his brother indicating he was murdered, he becomes involved in a shadowy world of spell battles and secret names. Together with the mysterious Soubi, the search to find Seimei's killer and uncover the truth begins!