Miki is a housewife who lives with her husband and son. Perhaps her libido has grown stronger as she has reached her forties, but her nighttime activities with her husband have become less frequent, leading to frustration. In an attempt to attract her husband's attention, she masturbates as she read in a book about how to increase her pheromones. When her son gets home, he peeks at her and runs upstairs so he won't notice. That night, Miki's back hurts and she asks her son for a massage. Next, Miki massages her son. She notices her son's penis, which has grown big, and can't help but stare at it...