With her husband away on a long-term work assignment and rarely returning home, Yukiko finds herself overwhelmed by loneliness. She has been engaged in a forbidden, passionate relationship with her cohabiting son, their mutual desire drawing them into an intense, intimate bond. However, one day, her son makes an unexpected request: "I want you to have sex with my private tutor." This proposition pulls Yukiko into even deeper emotional conflict and burning passion, leading to a series of events where love, lust, and familial ties become dangerously intertwined.