I'm a failure as a mother. Rin, who joined the Azuma family as a second wife, ended up having a physical relationship with her stepson and has always felt guilty towards her husband. In an attempt to restart their relationship, she tries to distance herself from her stepson, but he has learned the pleasure of sexual intercourse and is unstoppable. "Stepmother, is it good?" "No, stop it..." Rin protests with her words, but her body is already unable to live without her stepson...