Kim Jo-jo
Kim Jo-jo is a beautiful and hardworking high school student who is bright and cheerful despite her family's painful history. She lives with her maternal aunt and cousin after her parents died and has been working to pay off a debt her mother left behind.
- All of the Other Reindeer: She eventually becomes ostracized at school due to Sun-oh taking an interest in her.
- Beware the Nice Ones: Jo-jo is a nice girl who’s dealing with some serious issues. However, when her cousin threatens to tell everyone at school about Jeju Island, Jo-jo pushes her down and says that she’s a monster for thinking about doing that.
- Cinderella Plot: Jo-jo is forced to pay off a debt her parents left behind and she’s mistreated by her aunt and cousin who use her parents’ deaths to psychologically abuse her. She also gets involved with an attractive popular guy who her cousin is also interested in and tries to make Jo-jo break up with him.
- Dark and Troubled Past: Jo-jo has flashback of her time on Jeju Island, which resulted in her parents’ deaths and Jo-jo being traumatized.
- Dude Magnet: She manages to attract the attention of three guys, which are Il-sik, Hye-yeong, and Sun-oh.
- Not with Them for the Money: Contrary to what people say about her, Jo-jo likes Sun-oh for who he is, not for his celebrity status. This is one thing that makes him fall for her.
- Single Woman Seeks Good Man: Unlike other girls at her school, Jo-jo isn’t interested in Sun-oh for his popularity or his money, but because of how supportive and kind he is to her.
- Stepford Smiler: Type A. She presents herself in a cheerful manner at school, but is in truth holding onto a lot of pain from her past. She also has been keeping the pain of her cousin’s bullying from people at school.
Hwang Sun-oh
Sun-oh is a famous model who was away in the U.S. for a few years and returned home. He falls in love with Jo-jo and fights for her affections with his best friend Hye-yeong.
- Chick Magnet: His Love Alarm is constantly ringing due to him catching several girls’ attention.
- Ladykiller in Love: He has been with girls in the past and has several admirers around the world and at school. However, Jo-jo is the only one he’s interested in.
- Mr. Fanservice: He has a muscular build and occasionally has a shirtless scene.
Lee Hye-yeong
Hye-yeong in Sun-oh’s best friend since childhood and the son of one of Sun-oh’s servants. He works part-time at a bbq that Jo-jo works at and harbors romantic feelings for her.
Park Gul-mi
Gul-mi is Jo-jo’s cousin and classmate. She is the object of Duk-gu’s affections and is disgusted when she finds out that he likes her. She torments Jo-jo for being Sun-oh’s girlfriend and constantly threatens to tell people what happened at Jeju Island.
- Clashing Cousins: Most of her screen-time centers around her antagonizing Jo-jo.
- It's All About Me: Gul-mi is very conceited and thinks about her own needs before others’. If she doesn’t get her way, she retaliates in some way.
- Manipulative Bitch: She tells Sun-oh part of Jo-jo’s past in the hopes that her cousin will break up with Sun-oh. She also lies to her mom and pretends to be the victim so that she will hate Jo-jo.
- Never My Fault: She regularly blames Jo-jo and her parents for her misfortunes. During her fight with Jo-jo at school, she accused her cousin for being the reason why Sun-oh doesn’t ring her Love Alarm.
- Not Good with Rejection: When Sun-oh makes his interest in Jo-jo clearer, Gul-mi contemplates reporting Sun-oh by claiming he attacked her at school.
- Single Girl Seeks Most Popular Guy: She expresses an interest in international model Sun-oh. She considers him to be the only guy who’s worth her time.
- Wounded Gazelle Gambit: Her m.o. is to act like victim if she starts trouble with someone. She primarily does this with Jo-jo, resulting in her mother thinking that Jo-jo is the troublemaker.
