My niece is moving from the countryside to Tokyo to attend university, and until she finds a new home, she's going to live with me, her uncle. When I arrive at the meeting place, I find Kasumi, a grown-up woman. Once we start living together, she calls me into the bathroom, shows me her masturbation... I'm perplexed by her wild and vulnerable behavior. Then, one day, Kasumi says to me, "Uncle..."