Haeun and Joshua hated each other. Ever since they were kids, they were always competing and arguing. Haeun was the rebellious and funny girl in school, and Joshua was the quiet and normal guy who played in a band. They had nothing in common, except for Haeun's brother, Soonyoung, who was Joshua's best friend.
Haeun thought Joshua was a boring nerd, who only cared about music and his band. Joshua thought was a wild troublemaker, who only cared about pranks and jokes. They avoided each other as much as possible, but they couldn't escape their mutual presence in Soonyoung's life.
Things got worse when they were assigned to tutor each other for their final exams.