Yui Hatano and her husband initially resisted the idea of her being with another man. But contrary to her feelings, Yui's body began craving sex with other men. Drawn into Hibiki Otsuki and her husband's clever scheme, the Hatano couple awaken to a new sexual experience—swinging. Enthralled by the pleasure of enjoying sex with different partners, they gradually accept the idea of a 4P. Though initially shy, witnessing their partners having sex triggers unexpected impulses, making them climax harder than ever before. Where will the path of NTR ultimately lead the Hatano couple?