Mei Satsuki and Naoya suddenly became family due to their parents' marriage. As a female college student, Mei treated Naoya with the same sharp, aloof attitude she always had since childhood, so he never saw her as a woman. However, Mei actually had strong feelings for Naoya but couldn't be honest about them due to fear of what others might think. One day, she began deliberately seeking moments alone with him, using explicit, seductive talk to turn him on. These dirty words expressed her true feelings and started to stir emotions in Naoya. Gradually, he began noticing Mei's words and behavior. Their relationship slowly grew deeper, inching closer to intimacy.