When Naho received a letter from her future self, it told her she needed to save the life of a boy in her class, Kakeru. At first, Naho had to shoulder this burden alone, until her friends revealed that they had also received letters from the future. Working together, they were able to save Kakeru's life, and Naho and Kakeru started dating. But what happens next for Naho's friends, now that they're living in this brand-new timeline?