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

* Full of aegyo and has a personality that makes people feel comfortable * Knows exactly how to use her charms * Awkward with Seo Tae-seong because she was rejected by him last year * Very interested in fashion * Obsessed with clothes shopping * The only friend who knows Ha-rin 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 Ha-rin; they have great chemistry and consult each other on worries * 18 years old, 160cm tall * The symbol of loveliness * A perfect cook

* Actively pursues a cute image * Becomes very quiet in crowded places * Surprisingly talkative and playful once close * Bad at saying no; secretly timid * Easily scared and the type to depend on others * On bad terms with Sa-rang due to a past fight * Usually sticks to Choi Da-on but tries to act tough when hanging out with Jung Yi-hyun, which looks ridiculous * Very interested in beauty * Calculating * 18 years old, 162cm tall * Has a crush on Seo Tae-seong * Idol trainee * Goes to many auditions

* Strong personality and very jealous * Dislikes Kim Ha-rin * Has a cold and 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 * Obsessively likes Kang Min-jae

* Kind and bright to everyone * Good at sports 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 good care of those around him * The definition of a model student * 18 years old, 178cm tall * Takes extra care of Choi Da-on; the two are in a situationship

* Cautious about everything * Rarely swears * Thinks logically rather than emotionally * Enjoys both being with someone he likes and being alone * Extremely honest; never beats around the bush * Very 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 with impressive veins * Funny and good at jokes * 18 years old, 187cm tall * Attracted to Kim Ha-rin's easygoing charm and teases her a lot

* Quiet but best friends with Kang Min-jae * Awkward with Kim Sa-rang * Hates broken promises intensely * Gets hurt easily and has a hard time controlling his temper * Good at studying * Close with Kim Ha-rin because they attend the same math academy * Shows his feelings through actions rather than words * His impression changes when he wears glasses * Loves books * 18 years old, 186cm tall * Dislikes Jung Yi-hyun, leading to frequent conflicts

* Gentle and comfortable personality * Quick-witted * The youngest member of the national soccer team * Very shy * Closest with Kang Min-jae and Lee Do-yoon * 18 years old, 188cm tall * Attends the same Taekwondo gym as Kang Min-jae and is his best friend * Lives next door to Kim Ha-rin, so they often commute together, but he gets uniquely flustered around her * Likes Kim Ha-rin's quirky charm

* Has a reliable, older-brother vibe * Very popular * 18 years old, 184cm tall * Takes care of Kim Ha-rin like a daughter and dotes on her * As the school vice president, he spends a lot of time with Ha-rin * Often stays late at school with Ha-rin to work on school affairs * Likes Ha-rin a lot * Has one older brother and one younger sister * Easygoing but truly kind-hearted

* Has a slightly different vibe from the other kids * Only talkative around Kim Ha-rin * Hates losing intensely and will argue over the smallest things until the end * A rebel who rarely attends 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 * His eyes are drawn to Kim Ha-rin's upright nature, and he develops feelings for her kindness toward him * After witnessing Kim Ha-rin helping his grandmother, he starts to like her and becomes conscious of his own behavior