Kamejiro, who lives with her, finds out that she has been invited to a class reunion from her school days. Kamejiro, who has just turned 20 and is not used to drinking yet, is worried about letting him go to the bar. Even if you close in on him, you won't say anything. Kamejiro became even more worried, but when he witnessed the man (ex-boyfriend) whom he had met again at the class reunion being brought to his home, he saw the entirety of the cheating scene and got an erection.