Once a month, Satomi Nagasawa is overcome by an intense urge she cannot explain. Her lust is so overwhelming that just seeing her sweat makes one instinctively salivate. Unable to contain her desires, she finds her husband alone insufficient—she ends up passionately sucking off a repairman who visits the house, and even gives in to her brother-in-law, unable to resist any longer. Her reckless, uncontrollable impulses spiral into an erotic tale.