On the first day of the second semester, Yuzuru Kazuki finds himself suddenly trapped in a phenomenon where he repeats the same day. The reason is unknown. Faced with something that cannot be explained by science, Yuzuru feels helpless. However, changes begin to emerge within the repeating days. The first time——a love letter was dropped into his shoe locker, but he ignored it because the girl didn’t specify where she would be waiting. The second time——the love letter had a meeting place written on it. When he went, he was confessed to and rejected the confession. The third time——there was no love letter, but the girl who wrote the love letter approached him directly. Unlike other people, the girl takes different actions every time. But then, she casually muttered, 「——I can just start over again.」 Upon hearing this line, he starts to think that the cause of this phenomenon is her, Akari Sakurazaka.