Kikue has had no physical relationship with her husband for over seven years. One day, she discovers her son masturbating. Though she initially considers reprimanding him as a mother should, she notices his penis hardening inside his pants, triggering a surge of pent-up desire built up over seven long years. In that moment, she gives in and takes her son's penis into her mouth. From that instant, their relationship takes a drastic and irreversible turn.