After losing her husband, Takashima Midori raised her only son, Takahiro, single-handedly. However, struggling with insufficient income, she was forced to offer her body to her boss, Oonuki, in exchange for financial support. Oonuki, harboring perverse desires, wasn't satisfied merely possessing Midori—he gradually developed an intense obsession with her anus. Desperate to survive, Midori obediently allowed him to repeatedly toy with her back passage, until eventually he took her anal virginity. Unable to withstand the sensation, she shamefully reached a climax. Witnessing her helpless ecstasy, Oonuki grew even more aroused and began devising a new, twisted plan...