With her husband away on a long assignment, frustrated Nami burns off her pent-up desire through exercise. While training with her adult son's athletic friend Kosuke, she notices his erection and playfully tempts him. What was meant to be a casual taste turns overwhelming when his stamina never fades no matter how many times he ejaculates. He keeps fucking her into countless orgasms until the pleasure becomes almost maddening and her exhausted body begins to scream.