Jisoo and Hyun-oh have been dating for three years. One day, Hyun-oh, who had gone abroad for a language study program, suddenly decides not to return home on the promised date, leaving Jisoo feeling disappointed. Coincidentally, Jisoo ends up celebrating his birthday at the house of Hyunjae, his tutoring student. Angry at Hyun-oh, who only seems to play pranks on him, Jisoo teases Hyunjae by asking if he wants to try finding the piercings on his body. Hyunjae, who has a secret crush on Jisoo, begins to search for the piercings with his lips. But then, Hyun-oh, who was supposed to be abroad, suddenly appears before them "If you're going to do it with another guy, you should have shown me. Right?"