Mother and Seiko, along with her son Takeshi, shared an intensely close bond, affirming their love for each other every day. One day, Takeshi catches his mother secretly giving money to her pimp. When the three of them try to talk it out, Takeshi flies into a rage, ties up his mother, and rapes her right in front of Seiko. Initially resisting, his mother gradually begins to moan, surrendering herself to the pleasure. The humiliation and arousal of being taken right before her beloved son's eyes ignite her desire, driving her toward climax after climax.