Lee Donghae (age 17) – smart but shy senior student, has a major crush on Eunhyuk ever since he sat in front of him in biology class last year. His parents are both successful surgeons, with his father being the top neurosurgeon at SM General Hospital. First moved to the district two years ago and has trouble making many friends, but is close friends with Kyuhyun, Yesung, and Siwon.

Lee Hyuk-Jae (Eunhyuk) (age 18) - handsome, reserved senior student often stalked by obsessive girls from lower grades. Is the wealthy heir of a large company (Lee Corporation) founded by his grandfather. Despite his rich background, Eunhyuk rarely displays his family's rich status and prefers to blend in with others. He is moderately popular, being friends with Kangin, Heechul, and Leeteuk. He is a bit of a slacker in academics but is very passionate about hip hop/R&B dance and is the leader of a school dance/rap group.

Cho Kyuhyun (18) – gaming nerd, intelligent and competes with Donghae for the highest test scores in the class.

Kim Ryeowook (17) - piano prodigy, extremely smart and tops every class, oddball sense of humor, very caring/understanding

Choi Siwon (18)– Son of a prestigious and extremely wealthy family, heir to the Choi estate. Is steadily dating Kim So Hyun.

Kim So Hyun (17) - OC, pretty and popular girl at Woon, daughter of a CEO of an airline company, manipulative 

Other characters include Kangin, Heechul, and Yesung