A mysterious fire suddenly breaks out at Hakusen Academy. As the students are filled with fear, Shinkai Sho rushes around trying to save his younger sister, Shinkai Ten. Kujo Miyako, who seems to know something, offers to help Sho. As Sho and Miyako search for the cause of the fire, a supernatural being with the ability to freely control flames appears before them. Facing a threat that cannot be countered by common sense, Miyako activates her powers using an accessory called an "Artifact," which bestows special abilities. As danger looms, the two join forces to face the supernatural being. What fate awaits them at the end of the battle?