After losing her husband, Keiko now lives alone with her son. As her son has grown into adulthood, she has begun to see herself again as a "woman." Her son's friend, Matsuda, comes to stay with them for just one day, becoming a temporary "mother" figure to him. As Keiko takes care of Matsuda, who has no parents of his own, their bond deepens, awakening desires she had long forgotten. Driven by these intense feelings, Keiko trembles with physical pleasure and gives in completely to her uncontrollable passion.