Satoru Ichihashi is an average delivery man in a secret relationship with the head of the Aikawa Corp, Yukiya Kaji. He adores Yukiya's refined nature every time they meet up. And despite Yukiya having a family, Satoru is still besotted with the older man.

But everything becomes complicated when Yukiya's son, Kyosuke Kaji, visits Satoru's workplace to demand that Satoru break up with his father. Satoru vehemently refuses, saying that there's no other man besides Yukiya and even dares Kyosuke that if he satisfies him better than his father, he might change his mind. To Satoru's chagrin, Kyosuke takes the dare a bit more seriously than he thought.