Yamada, a part-time worker who only thinks about butts, has his niece Ena come to stay at his house. Ena doesn't listen to what people say and just plays games all day long. She exposes her beautiful butt without any protection... Yamada can't help but bury his face in Ena's butt... At first he is surprised by this sudden act, but halfway through he starts to enjoy it and starts asking for more and more, as if he is toying with her uncle... From that day on, their secret relationship began.