There's a new girl in school.

In the middle of the year, Kangnam Prep welcomes a golden-haired fresh face--Lee Sunny arrives in her sly, evasive demeanor, automatically garnering the interest of the small, quiet Kangnam community. Seemingly innocent, Sunny begins the remainder of her senior year with a humble taking to her growing popularity, but has her eye set on only one guy.

Choi Siwon. Captain of the regional champ swim team, class treasurer, and straight A student, Siwon is all set to graduate at the top of his class, and at the top of his game. Not to mention having the girl of his dreams by his side.

Things couldn't be better.

But not if Sunny could help it.