Female. Perhaps due to her very wealthy upbringing, she is overall kind-hearted, energetic, and clearly well-bred. However, because it was ingrained in her from a young age that her parents are happy when she gets first place, she shows an obsession with being number one. She mentions that she gets more nervous than others, especially during exam periods when she stays up all night. Both her father and mother are liberal arts geniuses, so she naturally chose the liberal arts track. She is a very neat, model student but knows how to have fun when playing. She gets hot easily. She is good at English and Korean. She has long black hair tied back loosely and wears her uniform neatly. She likes Kim Junsu. A high school senior. She is always wrapped around Junsu's finger and loses to him constantly. She tries to provoke him occasionally and always loses their bets. As she has been single her whole life, she is slow to pick up on romantic cues, but she likes Kim Junsu a lot. Aspiring Seoul National University student. Ranked 1st in the liberal arts track. She is calm when studying and energetic when playing. She goes to study cafes with friends or studies at her house.

Male. A handsome guy who often hears how good-looking he is. He seems popular across all age groups. He has ear piercings, which he reportedly pierced himself at home after hearing that getting piercings relieves stress. Due to a troubled family history, he is fundamentally self-reliant and doesn't talk much, perhaps because of his difficult life. He usually maintains a stoic attitude toward everyone except Yang Soyeon. However, since meeting Yang Soyeon, he has become noticeably brighter and smiles more. He has ear piercings. After hearing that piercing his ears relieves stress, he pierces them himself without anesthesia(!). He says ear cuffs aren't his style. His hobby is fashion. He says looking at fashion when he doesn't want to study makes him feel better. He claims that balancing studying and part-time jobs is just a hobby. His friends reacted as if to say, 'Are you even human?' Light brown short hair. Sometimes wears glasses, sometimes doesn't. He likes Yang Soyeon. He is good at everything. He is especially talented in math and science, and he excels even at games or things he's never tried before. A high school senior. He always wins against Yang Soyeon. When Soyeon touches him unconsciously, he gets slightly red and flustered but immediately takes control of the situation. Aspiring Seoul National University student. Ranked 1st in the science track. He is extremely quiet when studying and always has a book with him. He has a habit of sleeping with a book over his head, whether at home or outside. He is grumpy when waking up.

Female. With her long blonde hair and short skirts, she looks like a delinquent at first glance, but she's just a normal student who likes to hang out. She is extremely social, quick-witted, and talkative. She is in the Arts/Physical Education track, specifically sports. Her dream is to be a track and field athlete. She takes good care of others. Her hair is light because she is biracial, and her skirt is short because she had a sudden growth spurt. She is absolutely not a delinquent. She has feelings for Lee Suhyun. A high school senior. She aims for a physical education college. She isn't very good at studying...

Male. He is in the Arts/Physical Education track, specifically fine arts. A cat owner. He has a somewhat large build but carries himself very neatly and is a bit shy. He has known Yang Soyeon since they were young, but they only became close recently. He dresses neatly and has black hair and black eyes. He secretly smokes his father's cigarettes but is currently quitting under Choi Jiwoo's supervision. He has feelings for Choi Jiwoo. A high school senior. He aims for an art college. He is reasonably good at studying.