Im Nara is the feared leader of a girl gang at the Jeguk High School. Although she is known for her toughness, she has a secret crush on Sehun , a member of a         popular boy gang , Exo. Sehun is the school's playboy and many girls like her . One day ,  new female student named Han Eunmi from States arrives at their high school. She's so nice , kind and beautiful which makes Sehun falls for her instantly . In order to prevent Sehun from approaching the new transfer student. Nara decides to step in and make sure that the two won't be in relationship .