College student Yuki (Anna Ishibashi) is reunited by chance with Jun (Shunya Shiraishi), a junior high school classmate. Jun confesses his love for her, but Yuki chooses Kazuya (Sho Jinnai), a senior in the same club whom she has secretly admired. The relationship between Yuki and Kazuya seems to go well, but Kazuya has an affair with a girl whom he has dated before. Yuki decides to say good-bye, and Jun asks Yuki to come back. However, Yuki cannot cut off her relationship with Kazuya. Swaying between the two men leads Yuki into an unexpected tragedy.
Kaori (Rino Sashihara) is in love with a classmate, Horiuchi (Riku Ozeki), who gave her an eraser when they were both first graders. There is no progress at all, yet Kaori deepens her feelings for him. With the sole desire to remain close to him, she dedicates herself to studying and passes difficult examinations to enter the same high school and university. Horiuchi breaks Yuki' s heart in high school by saying, "You are only a classmate." But Kaori never gives up. After 13 years of unrequited love, the surprising truth comes out.