Woollim Girls High School had announced a compulsory summer camp, which would be combined with their affiliated boys school, BigHit Boys High School. You'd think the girls would be swooning over the boys and vice versa, right? Wrong. Contrary to popular belief, the girls and guys despise each other and have beef with each other. They're basically cats and dogs. To their horror, they'll have to survive the whole summer with each other. Who knows what would happen throughout the summer? Rivalry, hair-pulling, collar-tugging and... romance?