Asaka Natsumi, who just entered high school, heard an unbelievable story from her classmates in the first Homeroom on the day of the Entrance Ceremony. "In other words, all the students and teachers in this class except me have repeated the same year 12 times?" From then on began her High School life surrounded by her classmates who seemed as if they had attained enlightenment, her fun and happy day. ——Till a year later, March 31, when it would end.