The drama starts when the girl falls from the bus into the arm of Yoochun. Uknow enters the drama afetr few seconds to beat the bad guys. The girl breaks the side mirror of U-know's bike by throwing basket ball towards him (as he asks for the ball). The girl runs after that and falls on the ground. In hurry she leaves her one shoe there and Yoochun picks it up. And THE FIRST LOVE starts.
I am not going to reveal the entire story but seriously I really loved the script. I would really recommend to watch this. This show is all about how Yunho and Yoochun try to get their ways to impress the girl. It has lots and lots of fun, action, romance and tragedy. It has all the elements of a good drama package.