One day, Shiraishi Itsumi dies at Seibo Maria Girls High School. She falls off from the rooftop of a school building. Itsumi is the administrator's daughter at the school, and she was envied by all the other students there. Did Itsumi kill herself, or was she killed accidentally or intentionally? At the time of her death, she held a lily of the valley flower in her hand. A rumor spreads that somebody
