Reio Mikami is a 14-year-old boy in a single-parent family. Because his mother was dispatched for overseas work, he had to live alone in the small farmhouse left by his grandfather.
Mikami, who came to this small town from a big city, was full of curiosity about his neighbor, Teng Ushun, a mysterious and somewhat morbid boy of the same age who didn't go out much. Mikami tried to ask other neighbors several times, but every time she was met with forbearing expressions. This made Mikami full of thoughts about Fujiu to find out.
Mikami came to this small town during the most changing years of his life. In the process of exploring his neighbor Fujiu, he gradually became harmonious with Fujiu and spent three years.
While Mikami noticed the growth and changes in his body, he also noticed that Fujiu was almost undeveloped. And as long as this question is asked a little bit, Fujiu will leave the side almost as if he is running away.
Until one day, Mikami discovered a photo album of his grandfather's childhood. In it, there was a young man who looked exactly like Fujiu. On the list on the back of the album, "Fujiu Shun" was clearly written. Mikami couldn't accept this fact and ran to question Fujiyu, who told him: "There are three types of people in this world. One is children who can't wait to become adults, one is adults who want to be young again at all costs, and the other is people who stay at 14 years old and cannot grow up, no matter whether they want it or not..."