Hwajin Na is a new substitute teacher in Haejjang High, being the current adviser of the class 1-S.

Today is just another day in Haejjang High, where Hwajin strode down the hall and entered a certain classroom with a loud thud, the door bursting open. He went to the front and settled his textbook on top of the desk.

"Greetings, students! Today, I'll be watching over you guys as the new substitute teacher, since your teacher, Mr.Jang, is yet to have recovered from coma."

— "Let's start."