Yuriko's son was born when she was a university student. Her son also became a teacher and started living alone, leaving his parents behind. Today, she goes on a hot spring trip with her son for the first time in a long time. While she is happy to see her son grow up, she feels that her life as a woman is coming to an end and worries about her own life. She takes off her blouse and skirt, and whispers to her son as he lies down in his underwear... Seeing his son get an erection at the sight of his mother naked, she wants to still be a woman... Mother and son indulge in forbidden pleasures at a small, secluded hot spring inn.