Yui has overcome the hardships of being a single parent and has raised her son Keita on her own. Whether he knew about Yui's struggles or not, Keita has grown into a strong man who loves his mother. One day, while Keita is at home, Yui and, for some reason, Keita's best friend, Tooru, come home together. "Keita... Your mother and Tooru got married." Keita is taken aback and shocked, while Yui and Tooru look at each other happily. Keita can't bring himself to get angry at such a happy couple...