Set in a world where the supernatural no longer exists, scientists discover a way to harness the power of the past by creating bracelets known as raiki. The story follows teenage boy Muramasa Shinzu and his brothers, Ganix and Kalino, after the loss of their mother to an unknown disease. Moved to an orphanage and forced to enroll in the infamous Crimson High, a school where students viciously kill each other, Shinzu realizes the one who stands at the top of this institution. He decides to become the next Crimson King as he uncovers the reason for his father's disappearance.