The story is about Riko Komukai, the second daughter of the Komukai family who has grown up equally between the capable eldest daughter and the third daughter who is a free woman. She is engaged in dispatch work in Tokyo.Taking the death of their grandfather as an opportunity, the three sisters of Xiaoxiang's family got together. After 4 years, the whole family was finally reunited.

When Riko was sorting out her grandfather's belongings, she discovered a half-made plastic model. She met Yajima at the “Yajima Model Shop” where her grandfather often visited during his lifetime. Under his guidance, she began to try to make plastic models.Through the plastic model, Li Zi got a little understanding of her grandfather and his family. She decided to stay in her hometown during the summer to make up for her grandfather's regrets.