You: A Junior at SM High School. Your mom passed away when you were 8 and you only have a older twin brother named Choi Minwoo and your dad. But you have one secert that the world doesn't know except for your family and your best friend. You never blame anyone for your sickness. But you don't want anyone else to know. On the other hand you are a happy person and very smart. You never fail to smile and very good with aegyo. 

Yong JunHyung: A Senior at Cube High School. Known as the badass of the school. He's from a rich family. He hangs out with 5 friends and at their school they are known as B2ST. He's very cold and never seems like he talks. The only peron that can make him smile is you. What will happen when he falls in love you?

Tiffany(SNSD): Your best friend in this whole wide world. You guys have known each other before moving to Seoul. She's your best friend that knows your secret. She's always there when you need her. But then she also has a secret of her own. She's in love with your older brother Minwoo.