Miki finds herself encountering her son's friend, Kosuke, in the middle of masturbating when he's staying over at her house. Amused and playfully tempted by his embarrassment, Miki invites him for a drink and begins seducing him. Kosuke's huge cock, unsatisfied with just one release, repeatedly pounds Miki's body, climaxing over and over again. After that night, Kosuke keeps visiting the house, continuing their affair. However, due to his insatiable stamina, Miki's body gradually reaches its limit, and despite her suffering, she finds herself helplessly drawn deeper into the relationship.