Unbalance x Unbalance

Jin-Ho Myung returns a wallet and cell phone to a beautiful young woman (Hae-Young Nah) in a book shop, little realizing that she would find out that he has already (rather presumptuously) taken 7000 won to buy a book he really wanted. The woman in question is understandably rather upset but decides to consider the money as a loan, which she expects to be paid back. On the first day of the new school year, he learns, to his horror, that the very same woman is to be his new homeroom teacher. The bad news for Jin-Ho is that she remembers their previous encounter very well.

Characters:
Myung, Jin-Ho [Main] - The male protagonist of the series. He is a student in his final year at Arim High School and finds himself a student in Hae-Young's class. Seemingly caring little for schoolwork, he has been known to go to the nurse's office to sleep, watch erotic movies in school, and complete mathematics tests (generally unsuccessfully) using pure guesswork. In middle school, it appears he was something of a delinquent who got into many fights, becoming quite skilled along the way. When it comes to his teachers, friends, or family, he takes their physical abuse and, in most cases, takes the blame and punishments simply because he can (especially early on in the story). This has been a source of concern to his family, or at the very least for his aunt who usually acts more like an older sister than a parent figure. However, he can also become focused if something interests him, like film, which caused him to be the co-founder and eventually the president of the school's Film Studies Club.

Nah, Hae-Young [Main] - The female protagonist of the series. A beautiful young woman in her mid-20's, Hae-Young teaches mathematics at Arim High and also acts as the homeroom teacher for class 3-2. She lives with her sister and niece in an apartment block quite close to Jin-Ho's. Her father's unexpected departure from her life when she was young has had a huge impact on her. Even though she is extremely attractive and was apparently popular (and pursued) throughout her school life, she has become very guarded around men, feeling unable to trust or form relationships with them. Consequently, she is still a virgin and even shares her first kiss with Jin-Ho during the course of the story.

Cha, Young-Gi - Jin-Ho's friend and classmate. They have been placed together in the same class for the previous six years. Like his friend, he is skilled at fighting. It has been implied that he likes Ji-Soo; he is very protective of her and careful of how she perceives him. Young-Gi also has a strong sense of justice and, despite his tall, athletic build, prefers to find the most peaceful resolutions to otherwise violent confrontations. His first encounter with Jin-Ho was back in middle school when Jin-Ho, who was a notable delinquent at the time, was harassing another student; the two fought and soon afterwards became close friends.

Eun, Ami - She is a senior and a friend of Ji-Soo. She is shy and quiet at school, where she often reads yaoi manhwa. She is one of the first to find out about Hae-Young and Jin-Ho's complicated out-of-school relationship. When Jin-Ho learns that she is the one who told Ji-Soo about his situation with Hae-Young, he attempts to confront her. During this face-off, she threatens to publicly reveal the relationship, which would be likely to get Jin-Ho suspended and, even worse for him, ruin Hae-Young’s career. She even forces Jin-Ho to kneel in front of her without a second thought so as to exert her power over him, and gets pleasure out of it. She seems to not like men in general, and also appears to dislike Jin-Ho in particular. It transpires that this was an empty threat on Ami's part, since she herself is also in love with Hae-Young; she even tries to force herself on her teacher, who then turns her down.

Ha, Ji-Soo - The senior class president as well as now being the president of the Student Council. She is hardworking, studious, performs well and is also popular. She appears to have liked Jin-Ho ever since her freshmen year of high school, when he helped her make origami flowers. He does not feel the same way towards her, though at one point he does suddenly notice that she is attractive.

Myung, Ji-Sun - Jin-Ho's screen writer aunt who lives with him and his father. She often talks to and looks out for her nephew and is not afraid of hitting him when she thinks he has gone out of line. She also acts to diffuse the tension between Jin-Ho and his rather authoritarian and distant father.

Park, Jae-Kyung - She is a college freshman and a friend of Jin-Ho's. In her high school days (where it is revealed she had short hair), she was the co-founder and former president of the Film Studies Club (now passed on to Jin-Ho) as well as the former president of the Student Council (which is now succeeded by Ji-Soo). Even though she flirts with him, Jin-Ho feels comfortable enough with her to confide his girl problems to her. There are also hints that Jin-Ho may have had rather deeper feelings for her while she was in high school, and seems that Jin-Ho has been rather more distant with girls since she left.

Pendleton, Caroline - Nicknamed "Carrie", she is an Eurasian (half Korean/half British) woman who has recently arrived in Korea. She has lived in the United States for a while, learning the French martial art of savate. She has come to Korea because she is curious about her father's homeland and her siblings, who turn out to be Hae-Young and Hae-Jung. When she first arrives, she lives in a temporarily motel while her father arranges for her to stay with her half-sisters for about a month. She has been employed at Arim High as an English teacher and an assistant homeroom teacher under Hae-Young. It is revealed by Hae-Jung that her Korean name is Hae-Eun Nah. Whether she changed her name while living in America or while living in Britain remains unknown.