Jessica Jung Sooyeon - queenka of SM University on her 4th year as a doctor.  20 years old.  Cold appearance but gentle heart & mind in the inside.  Friends with Kim Hyoyeon.

Kim Hyoyeon - queenka of TS University on her 3rd year in Business Management.  The inheritor of the Kim Comp. since her sister Taeyeon is going to manage Kim Hotels while their one and only brother Kim Jongin is managing Kim Electronics.  19 years old.  Classmates with Jessica during middle school but she stopped studying for a year to hone her dancing skills along with Kai (Jongin).  Girlfriend of Byun Baekhyun.  Tries setting Jessica up with Baekhyun's step brother who is a half-Korean and half-Chinese.

Xi Luhan - brought by his stepbrother to Korea since he lived in China for 13 years already and he needs to take a break from seeing Chinese people and get to know his father's side's nation and country.  Planning to study at SM University in the Medical Department, Doctor course.  21 years old but during 5th grade he slacked off and eventually repeated 5th grade.

Byun Baekhyun - kingka of SM University along with Oh Sehun and Huang ZiTao.  4th year in Business Management.  20 years old.  Younger step brother of Xi Luhan.  Boyfriend of Kim Hyoyeon.  Goes along with Hyoyeon's plan.