On the day of his group project presentation for first semester, Lee Seung-hyun was mistaken for a pervert on the subway to university and missed the presentation, ruining his grades. In order to recover his GPA and bring it back to the 3.x range, which is the minimum GPA necessary for job prospects, he struggled to scrape together money to enroll in the summer session. The class is once again based on group projects, and he discovers that a junior named Seo Chae-jun, who didn’t come to class, is actually the same person who had mistaken him for a pervert…? 'What grave sin did I commit to have to deal with this crazy bastard's nonsense during this golden summer break of my senior year?'