Kwon Yuri. You could say she is down to earth, smart, pretty, and nice. Never really had a first love. Recenlty moved back to Seoul with her best friend Jung Jessica. At first, she doesn't like MInho, but starts to warm up to him as he opens up.

Choi Minho. He is kingka of the school, a playboy, and handsome. Had his heart broken. Dates a girl, them dumps them a week later. Kim Jonghyun is his best friend. MInho is not sure of his feelings toward Yuri. He doesn't want his heart broken again. 

Jung Jessica. Often referred to as the ice princess. Moved back to Seoul with Yuri. Starts to fall in love with Kim Jonghyun.

Kim Jonghyun. The dino head. Also a player like MInho, but starts to have feelings toward Jessica

They all are in college