Today, too, he can hear his mother's moans... Worried about his mother, Reimi, who is sexually frustrated and only masturbates, her son takes an unexpected action. It's a forbidden act of filial piety, filling her loneliness with his body. Reimi is confused, but when she realizes that this is her son's way of showing kindness, she stops resisting and accepts. Having crossed the forbidden line, mother and son release all of their suppressed desires. They seek each other to the limits of their physical strength.