Shinya had not been intimate with his girlfriend Yui for a long time. After many requests and persuasions, she finally agreed to let him have sex with her next week. Finally, after a long wait, the day arrived! He rushed into Yui's house and found her seemingly asleep. Unable to resist any longer, Shinya had sex with her immediately! But when he saw the face of the person he was having sex with, he was shocked - it wasn't his girlfriend! When Yui returned, Shinya realized it was his girlfriend's mother, Rio. Rio had coincidentally come to her daughter's house to visit and never expected to be taken advantage of in this way by her daughter's boyfriend. She not only was not angry but also felt excited and satisfied. The two of them had a strained relationship with their spouses, so Rio had not been satisfied sexually for a long time. Shinya, with his large and strong member, was able to bring Rio to climax continuously, something her husband couldn't do for her. Since then, taking advantage of the situation, Rio continuously made Shinya have sex with her, satisfying her sexual desires, and Shinya himself could not resist the seductive body of the potential future mother-in-law...