"Eri-san ... Would you like to be a family with me?" Ryota, who lost her mother when she was young and grew up without knowing the warmth of her mother. It was inevitable to invite the feelings of a familiar woman who made her feel motherhood. Ryota has become unusually obsessed with her cousin Eri, who came to teach her studies as a tutor. "Eri-san ... I had a boyfriend ..." The fact that I was suddenly informed during class. The feelings that were swollen in Ryota peel off their fangs.