Takayama Tatsuo, a university student living in Tokyo, returns home to find his cousin Akiyoshi Yoshio and Yoshio's mother, Akiyoshi Taeko, temporarily staying at his house due to renovations. As Tatsuo resumes life at home, he finds himself overwhelmed by intense sexual desire for his mother, Kayo Takayama, leading him to repeatedly have sex with her until he ultimately cums inside her—a shocking act of mother-son incest. Meanwhile, Yoshio is tormented by his uncontrollable lust for his aunt Taeko, captivated by her beautiful back and shapely thighs. As daily tensions rise, Yoshio accidentally witnesses Tatsuo and his mother in the midst of their taboo affair. The story exposes the fragile bonds of family and the twisted nature of human desire.