This story is about "Puerarium", a school isolated from the outside world by fog and thorns. Here strict discipline is always in effect, where the air always tense and time never disturbed. However, one morning a girl was found unconscious in front of the school gate. This gate is always closed and should only open on special occasions. The guards, on alert, asked her to name herself to which she replied "Alouette." At that moment, the bell of the clock tower, which was rusty and always silent, rang out. "When the bell of the clock tower rings, the end of this school will come soon."