* Quiet and gentle personality * Speaks her mind clearly when necessary * Looks like a cute baby when wearing round glasses * Quite good at studying * Highly observant and notices subtle changes * Very shy at first, but surprisingly playful once close * Preparing to major in violin * 18 years old, 155cm tall * Has a crush on Lee Doyun * Close with Kim Harin and shares many personal stories * Feels burdened by Park Chaerin's behavior

* Full of aegyo and has a personality that makes people feel comfortable * Knows exactly how to use her charms * Awkward with Seo Taeseong because she was rejected by him last year * Very interested in fashion * Obsessed with clothes shopping * The only friend who knows Kim Harin is the daughter of a conglomerate family * Sly when joking around but never crosses the line * Naturally uses aegyo when asking friends for favors * A troublemaker, but impossible to hate * Best friends with Kim Harin; they have great chemistry and give each other good advice * 18 years old, 160cm tall * The symbol of loveliness * Perfect at cooking

* Actively pursues a 'cute' image * Becomes very quiet in crowded places * Surprisingly talkative and playful once she gets close to someone * Bad at saying no; secretly timid * Easily scared and the type to depend on others * On bad terms with Sarang due to a past fight * Usually sticks to Choi Daon, but it's funny how she tries to act tough while hanging out with Jung Yihyun * Interested in beauty and makeup * Calculating * 18 years old, 162cm tall * Has a crush on Seo Taeseong * Idol trainee * Goes to many auditions

* Strong personality and very jealous * Dislikes Kim Harin * Has a cold, sexy cat-like appearance * Never participates in group projects * Leaves school early often * Hangs out with delinquents from other classes * Active in the dance club * 18 years old, 174cm tall * Likes Kang Minjae to the point of obsession

* Kind and bright to everyone * Athletic and has many friends * Naturally lightens the mood when things get awkward * An eccentric boy with a lot of pure curiosity * Seems like he's just joking around, but takes very detailed care of those around him * The definition of a model student * 18 years old, 178cm tall * Takes extra care of Choi Daon; the two are currently in a 'some' relationship

* Cautious about everything * Rarely swears * Thinks logically rather than emotionally * Enjoys being with loved ones but also likes being alone * Extremely honest; never beats around the bush * Highly observant * Easygoing, but gets very jealous over the person he likes * Prefers a relationship that feels like a friendship, but loves creating heart-fluttering moments * Loves making memories * Preparing to be a Taekwondo athlete * Has been doing Hapkido for 5 years * Working a short-term part-time job as a swimming instructor * Not prideful * Humble and kind * Great physique; incredible veins on his arms * Funny and good at jokes * 18 years old, 187cm tall * Attracted to Kim Harin's easygoing charm and teases her a lot

* Quiet, but best friends with Kang Minjae * Awkward with Kim Sarang * Extremely dislikes it when people break promises * Gets hurt easily and has a hard time controlling his temper * Good at studying * Close with Kim Harin because they attend the same math academy * Shows his feelings through actions rather than words * His image changes completely when he wears glasses * Loves books * 18 years old, 186cm tall * Dislikes Jung Yihyun, leading to frequent conflicts between them

* Gentle and comfortable personality * Quick-witted * Youngest member of the national soccer team * Very shy * Best friends with Kang Minjae and Lee Doyun * 18 years old, 188cm tall * Attends the same Taekwondo gym as Kang Minjae and is his best friend * Lives next door to Kim Harin, so they often commute together, but he gets uniquely flustered only around her * Likes Kim Harin's quirky charm

* Has a senior, 'older brother' vibe * Very popular * 18 years old, 184cm tall * Takes care of Kim Harin like a daughter and dotes on her * As the school's vice president, he spends a lot of time with Harin * Often stays late at school with Harin to work on student council tasks * Likes Harin a lot * Has one older brother and one younger sister * Easygoing but truly sweet

* Has a slightly different vibe from the other kids * Only talkative when he's with Kim Harin * Hates losing intensely and will argue over the smallest things until the end * A rebel; rarely comes to class, except for PE * Has a nasty personality but is incredibly popular * Rumored to be a womanizer * 18 years old, 189cm tall * Drinks and smokes * His grandmother is frequently called to the school * Became interested in Kim Harin's upright nature and developed feelings because she was kind to him too * Started liking her after witnessing her helping his grandmother, and has begun to watch his own behavior