After their parents remarry, his flashy gyaru stepsister treats him like a child because he looks young and constantly orders him around. Whenever she returns from the tanning salon, she makes him apply aftercare oil all over her body. Her slick, glistening skin leaves him hard, but because she considers him harmless, she never grows suspicious even when his hands approach intimate areas. To get revenge for all her bossing around, he gradually turns the oil rub into an erotic massage in this adult stepsibling role-play.