Fifty-year-old mother Ryoko lives alone with her son. She has an extremely strong sex drive and uses her son as an outlet for her desires. One day, her real brother, whom she had entrusted with some work, suddenly visits. Their reunion, stemming from a past romantic relationship, quickly evolves into an intense and erotic affair. The sex with her brother, justified by their long-awaited reunion, becomes deeper and more passionate. Meanwhile, her fierce sexual encounters with her son upon his return home go beyond the boundaries of motherhood, pulling her into a new whirlpool of desire. Her mature body and insatiable libido merge, transforming the middle-aged mother into a new woman consumed by lust.