Natsuko has been widowed for 10 years. She lives with her husband's stepson and father-in-law. Thanks to the insurance money her husband left her, they have been able to live comfortably, but she still feels something is missing. This is due to her recently growing sexual desire. Since her husband's death, Natsuko has not had a relationship with a man and has been satisfying her desires alone. But she never expected to end up in the arms of her "step" son and "step" father...