Three brothers return home to the countryside after hearing that their father, who lives alone in the countryside, has collapsed. However, his father has remarried without telling his sons. To a young woman who is like a daughter to him... The three brothers are smitten with their stepmother Saya, who exudes sex appeal. Taking advantage of their father being hospitalized, the three brothers, overflowing with sexual desire, make Saya, who has a frustrated body that they can't control, a slave to their incestuous penises...