Freeter Yamada, who only thinks about butts, had his niece Rinachan staying over. Rinachan wouldn't listen to anyone and played games all day long. She shamelessly exposed her beautiful butt… Yamada couldn't hold back and buried his face in Rinachan's butt… At first, she was surprised by the sudden act, but soon started to enjoy it, even teasing him for more… Their secret relationship began that day.
