Youdou (trimming) is a very introverted boy. He is a word of silence in the class and immersed in his own world all day. The newly -appointed teacher Aoyama (salt mouth) attracted the attention of You Dou. Unconsciously, the two began the move of exchange diary. Although he was not good at words, You Dou was good at telling his feelings in words. Over time, You Dou opened his heart to Qingshan. One day, You Dou did not go to school because he had a cold. The worrying Aoyama went to visit the door. The two were alone. In the ambiguous atmosphere, Qingshan failed to control his feelings and kissed You Dou. The great shock brought by Qingshan's kiss to You Dou's heart, he fiercely rejected Aoyama's love. After that, Aoyama resigned from the position of the teacher. The two never met again, and three years have passed.