Mao Yamaguchi enjoys masturbating alone in her bedroom. Suddenly, her husband appears with a vibrator, helping relieve his wife's pent-up desires. The couple indulges in their intimate moments, unaware that two shadowy figures have been secretly watching them every night. These observers are revealed to be Mao's sons. As family privacy collapses, their hidden desires begin to intertwine in an escalating web of incestuous tension.