Kim Jonghyun was a playboy. He had the looks, the brain, and riches. He had many girlfriends and the longest time he had one was for a week. He himself did not know why, they just could not stick. On 1 August 2013, however, he finally knew why, when he set his eyes on the new kid, Kim Kibum.

When Yoona captures the eye of the school's playboy, Lee Joon, he decides to make her fall for him, like the entire female population of Seoul High School had. But what's a plan without Joon failing as his own feelings get mixed up in the situation?