It's been a year since my father died in a car accident. Keiko's mother-in-law's discipline for Hiroshi became more radical with each passing day. As a punishment for soiling her pants, she was made to wear a diaper, instructed how to wash in the bathroom to satisfy her own desires, and was shown having sex with her friend in front of her... . One day, Hiroshi begins to have doubts about his grandfather who frequently visits his house. And Hiroshi finds out the real reason why his mother is so strict with him...