They were both extremely different from the other. 

He was the bad boy that everyone was scared of, no one had the guts to tell him go agaisnt his words. He wasn't mean at all he's just the most powerfull guy of the campus. At first he seems pretty normal but then when you'll get closer you'll feel this dark aura around him it will make you back up. He's arrogant, smart, extremly good looking, wealthy and someone you can count on when you'll get in trouble if you're one of his friends and only knows that he doesn't have much friends. He loves to party, drink, have and smoke. He always get what he wants. You better be on his good side or you'll live a real nightmare. He's the heir of Coex mall so you could guess that he have everything right? Jang Jieun? the only girl he kinda respect. It's not that he likes her or stuff like that it's just she's the kind of girl that bring respect. 

She's what we can call "miss perfect" she wasn't that perfect but that's how the other student sees her. Good grades, nice attitude, heiress of Samsung, good looking, honest, filial, treat everyone nicely. She have the face, the brain and the background. What a perfect combo right? She was not the kind of girl who'll say yes to eveyrhting and act like a puppy. Nope. She'll stand for what she thinks is right, she always give her opinion. If she likes you she'll give you the world but if she don't she'll just snob you. Kim jongin? not scare at all. She knows him since they're both babies. Their parents were not best friends but they already works together, when there was diner, conference or stuff like that their family would see each other and of course little Jongin and little Jieun would see eah other.

Just one night and everything change. For both of them.