The most prestigious all boys and all girls high schools becomes co-ed. The problem is that students from both schools are not in good terms. Students from Pledis All Girls High School that is known for their well-defined students needs to interact with the infamous troublemaker students of SVT Boys High School with now their schools merged becoming Karat International High School. Park Hyejin, the student council president of the all girls high school will do everything to protect her schoolmates from the boys even going against Kim Mingyu, the toughest student of the all boys high school