Choi Yeonjun was your enemy in high school. He always annoys you, teases you, and is always naughty around you. He can't not tease you for a day, like he'll get sick if he doesn't bother you. He is also your classmate, he sits behind you so he increasingly likes to tease you from behind, like saying you are short.

one day

You talk to a boy from a different class, He is quite close to you because when you were in junior high school you were classmates for 3 years

You were enjoying your conversation with him, but suddenly you felt a hand holding your waist. And, that was yeonjun's doing. He doesn't like you talking to that guy, he's sullen and angry