임재븜 Im Jae-bum(JB)
18 year-old, Seoul Royal High School grade three student, son of President Im from the Im's Group, the top 3 company in Seoul. A very handsome young man with a cold heart and bad temper. Everyone is scared of him, especially girls.
박진영 Park Jin-yong(Junior)
18 year-old, Seoul Royal High School grade three student, son of President Park from the Park's Group, the top 3 company in Seoul. A very handsome young man that wears a warm smile everywhere, very polite, kind-hearted and friendly. Has a fan club in school.
백은헤 Baek Eun-hye (portrayed by Kim Sae Ron)
18 year-old, from Busan. Moved to Seoul because of her father's job. Now a grade three student in Seoul Royal High School. A very outgoing and innocent girl, but clumsy and caring at the same time. Has a big sweet smile that can melt every boy's heart. She lost her memories at the age of eight due to an accident.
이현아 Lee Hyun-a (portrayed by AOA's Seol Hyun)
18 year-old, Seoul Royal High School grade three student. A very friendly and beautiful girl, but is shy in front of boys. Always hide her true feelings or worries, and is not willing to share them with others as she doesn't want others to worry about her.