Natsuko has been a widow for ten years, living with her husband's stepson and father-in-law. Thanks to the insurance money left by her husband, they live comfortably, but she always feels that something is missing in her life. This is because her sexual appetite has been growing lately. After her husband's death, Natsuko had never had a relationship with a man, and had been left to satisfy her own desires. But she never imagined that she would end up in the arms of her "stepson" and "stepfather"...