The narrator reflects on seeing the “100% perfect girl” for him while walking in the Harajuku neighborhood in Tokyo one April morning. He does not remember much about her appearance, except that she was neither very young nor very beautiful. Later, he thinks of what he should have said to the girl. He imagines a story in which an 18-year-old boy and a 16-year-old girl meet under similar circumstances and realize that they are 100% perfect for each other. They talk for a while and decide to test their discovery by going their separate ways: If they are really perfect for each other, they will find each other again. Years later, they both suffer from an influenza that causes them to forget much of their early lives. One day, when the boy is 32 and the girl is 30, they pass each other in Harajuku but do not stop, their memories of one another having grown too faint. The narrator decides that this story is what he should have said to the girl.