Rieko lived with her husband and son, and as her son had been working for several years, she began preparing for retirement. However, her son's company was a black enterprise, and he returned home mentally and physically broken, like a shell of himself. Worried, Rieko tried to talk to him, but he responded coldly, leaving the household filled with tension. During this time, Rieko secretly masturbated only when her son was away, but lately her body felt tense and unsatisfied. She invited her husband for sex, rekindling their intimacy after a long time. However, her son unexpectedly entered the room and witnessed them. Unaware at first, Rieko continued until her son forcibly took her. From that day on, her son's attitude changed completely, developing an intense obsession with her body.