Kinky Kyoichi is a serial cheater and makes love to different easy women. The salaryman meets with an old class-mate from university called Wataru. Surprisingly, or not, he is an investigator hired by Kyoichi's wife to look into the husband's infidelity. However, Wataru has a sexual offer of his own for his old school-mate. 一个传递。 大伴恭一（大仓忠义 饰），从学生时代起就只与“喜爱自己的女性”交往，不断重复着被动的恋爱，也因为优柔寡断的性格而不断地出轨。大学后辈今之濑涉（成田凌 饰）作为出轨调查员在接受主人公妻子的委托后，某日与前辈大伴恭一时隔7年再次相遇，突然向其告白「从很早以前就一直喜欢你了」，并用为其隐瞒出轨事实作为代价要求前辈以身体来交换。在被今之濑死缠烂打地靠近和追求下，最终恭一也体会到了如胸口揪心般的恋爱之痛…
