Lillet Blan arrives at the Tower of Silver Star to begin her schooling. During her first five days, she meets her teachers and fellow students. On her fifth evening, Lillet wakes to find the Tower under attack from Calvaros's released spirit, who has killed the other teachers and is seeking the Philosopher's Stone. Before he can kill her, the clock strikes midnight and she is sent back to the beginning of her first day at the Tower. During the next three loops of time, Lillet learns more about the Tower's inhabitants and her own situation.