My stepsister is usually plain and doesn't wear makeup. But I know it! I know that she's beautiful! The younger brother gives advice to his sister, who struggles with interpersonal relationships. This triggers her makeup skills to rapidly improve, and she gradually becomes more confident. Eventually, she transforms into a stunning beauty with a great figure that everyone turns to look at. However, as the younger brother, I can't stay silent. On a night when our parents are away, I impulsively confess my feelings, but she refuses me because we are "siblings." "It's okay if you don't insert it, just rub against each other..." Thus, the two of them make a promise to only do dry humping. But the two young people, unable to withstand just dry humping, end up crossing the line. They engage in raw sex that feels too good to stop. At first, it was just a physical relationship, but gradually their hearts connect, and they become lovers.
