Mayuki Ito had an argument with her husband so she was angry and left home, she went to her brother's brother's house to play to shun her husband's face for a while. Any doubt after passing the younger brother's house, looking at her younger brother, the day was extremely grown up, the house was big and beautiful, making her feel more affectionate with him, it seemed like they both liked each other from time to each other and then something came ...