Mari has been living with her son Satoshi since divorcing her husband three years ago. "Satoshi has been acting strange lately. Maybe it's because he's at that age, but I noticed that he keeps staring at my butt. As a mother, I get worried when I think about what he's thinking when he looks at me... Then, one day, something happened that finally upset our relationship. It was my fault for always wearing clothes that showed off my butt, but I never expected Satoshi to do something like that..."