Ayaba married an older man. Her husband remarried and they moved in together with their son, Tatsuya, and the three of them decided to build a new home together. Ayaba thought that she had a friendly relationship with Tatsuya, who is closer in age to her husband. However, contrary to this, Tatsuya fell in love with Ayaba as a woman, not as a stepmother. Without realizing their conflicting feelings, the two of them ended up spending a week alone together...