Ever since childhood, Ataru has been abused by his mother, leaving him with deep distrust toward women. One day, he meets Aoi, the mother of his friend Mitsuo. Radiating warmth and kindness unlike anything he's ever known, Aoi captivates Ataru, drawing him in and slowly helping him overcome his resentment toward women. But one day, he accidentally discovers Aoi masturbating. "N-No... Aoi wouldn't do something like that...!!!" The shock shatters his fragile emotions. His pure feelings twist into obsession, breeding a warped jealousy toward her son Mitsuo, which soon spirals into dangerous delusions. Ultimately, these emotions drive him toward increasingly reckless and perilous actions.