Mother Sawako and her son Sosuke lived together as a single-parent family. Sawako worked as a caregiver at the home of Takanari, a classmate of Sosuke's, taking care of Takanari's bedridden grandmother. Takanari's parents were stationed overseas, leaving only his grandmother and himself at home. Going through adolescence, Takanari gradually developed romantic feelings for Sawako and began seeing her as a woman. Unable to contain himself any longer, Takanari forcefully embraced her. Witnessing this incident, Sosuke was deeply shocked, profoundly disrupting the relationship between mother and son.