A girl who never had a boyfriend and a boy who is the bad boy made a deal. The deal pulls the girl from her comfort zone, and for the boy he will learn a thing or two about being nice. 

Lee Su Min, is a shy girl who is scared to reach out to people and talk to them freely. She admires people who were outgoing and has the courage to blurt out what was on their mind. She wanted to be that kind of person, but her insecurity didn't let her change. 

Kim Jong In, is the bad boy of the school; as people labeled him. He really just speaks whatever is on his mind, even if it's an insult he'll still blurt it out. They are rumors about him, that he is in a gang.