Mei and Naoya suddenly become a family when their parents get married. Mei, a female college student, treats Naoya with the same cold and distant attitude she did when she was a child, so naturally Naoya doesn't think of Mei as a woman. However, Mei actually loves Naoya, but she is worried about what other people think and can't be honest about him. However, she gathers up her courage and when they are alone, Mei uses various excuses to try to excite Naoya with dirty talk. Mei gradually starts to notice Mei...