Due to his deteriorating health, Marimi Natsuzaki's elderly father-in-law has become bedridden, forcing her to take on the role of caregiver. However, the real cause of his poor health is excessive drinking. Though Marimi pleads, "I won't drink anymore," he repeatedly sneaks alcohol whenever he gets the chance, leaving her frustrated and confused. Normally gentle and kind, the father-in-law transforms completely when drunk—quickly turning into a sexually aggressive man who harasses her without restraint, unsettling Marimi with his disturbing behavior. Confronted with his erect cock and lewd tongue, she struggles to maintain self-control, but her pent-up sexual frustration causes her body to react involuntarily. Gradually drawn into his drunken advances, Marimi succumbs completely, becoming her father-in-law's obedient drinking companion in an illicit incestuous affair filled with creampie sex.