While delivering a student's dry cleaning, Geum Jan Di saves the life of a heavily bullied student,Lee Min Ha/Lee Ji Ha, at the most prestigious school in South Korea. Her actions soon became public and exposes the bullying within the school, leading the public to go against the Shinhwa empire. To silence the public's attention, Jan Di is offered a swimming scholarship to Shinhwa High School which she declines but her family forces her to attend.
During her first day at Shinhwa, Jan Di learns of the famous F4 and of the other students' adoration and fixation with the boys in the group. Gu Jun Pyo, Yoon Ji Hoo, So Yi Jung, and Song Woo Bin are the richest and most powerful kids within Shinhwa and South Korea. Subsequently, they use their power to terrorize weaker students or those they do not like. Jan Di, instead of being impressed, becomes enraged and fantasizes about confronting Gu Jun Pyo, the leader and initiator of many of the bullying acts. She gains courage to confront him when a friend, Oh Min Ji, accidentally spills ice cream on his shoes and he demands the girl to lick it off. Jan Di defends her friend and attempts to reason with Jun Pyo's tyrannical demand. He refuses to relent and demands her to lick it herself. Acting like she's going to lick it, she bends down but shoves her own ice cream in his face. Enraged by this, Gu Jun Pyo declares war on Jan Di and encourages the other students to bully her. Jan Di, however, is resistant, refusing to apologize to Gu Jun Pyo, and stands by her decision to fight him.
Ironically, Gu Jun Pyo, having never been stood up to, begins to develop feelings for her. He tries unsuccessfully to woo her as she slowly begins to spend more time with Jun Pyo and his friends. But Jan Di has feelings towards Ji Hoo. Ji Hoo leaves For Paris, since Jan Di makes him realize that if he wants to have a serious relationship with Min Seo Hyun, he has to be close to her.
Jan Di teaches Jun Pyo that money cannot buy everything and in order to have real friends, he himself must be real or use his heart, but Gu Jun Pyo still does not understand why someone like Jan Di should dislike him.
Gu Jun Pyo declares to the school, that Jan Di is his girlfriend. While he is declaring it, Ji Hoo arrives back from Paris. Jun Pyo whisks Jan Di, the F4, and Jan Di's best friend, Ga Eul, off to New Caledonia. And to the annoyance of Jun Pyo, Jan Di and Ji Hoo are attracted to each other. One night, Ji Hoo kisses Jan Di. Jun Pyo see's it, and he breaks out in a raging fury towards them.
Jun Pyo leaves the island. Upon the groups return to Seul, Jun Pyo anounces that Ji Hoo is going to be expelled from the F4 and that he and Jan Di are both going to be expelled from the Shinhwa High School. But due to some races that Jun Pyo's older sister, Gu Jun Hee, orgiizes for them and the fact that Jun Pyo can't let go of Jan Di, they make up.
As the story progresses, Jun Pyo falls deeper in love with Jan Di and she learns how to open herself to his love as well.
Jan Di's best friend, Ga Eul often finds herself in the same place as Yi Jung. Though she finds him attractive, she is initially annoyed by his arrogance. One day, Yi Jung finds Ga Eul crying after she is dumped by her boyfriend. He advises her to let him go, and later, to make her feel better, Yi Jung takes her to have a make-over. The two go up to a club in which her ex is attending. Yi Jung pretends to be in love with Ga Eul to make her ex jealous. He gives her his scarf and walks her home, saying that if they're going to act, that they should act till the end. After this, Ga Eul finds herself smitten with Yi Jung. On Valentine's Day, she waits outside his house, planning to give him chocolates. He shows up with two girls on his arm and on his table, he already has dozens of chocolates from other girls. Ga Eul is upset, so Yi Jung reminds her that their night at the club was only an act, and it's not his fault if she took it too seriously. Yi Jung feels bad, and gives Ga Eul a cake and flowers, when he mistakenly thinks it's her birthday. The two become friendly again.
As love begins to blossom between Jan Di and Jun Pyo, Jun Pyo's mother discovers them and deems it unsuitable. She does everything in her power to keep the two apart, even arranging a marriage for Jun Pyo. The other F4 members and Ga Eul try to bring them back together. Yi Jung and Song Woo Bin came up with a few plans, but they fail. They resort to So Yi Jung and Ga Eul pretending to go on a fake date, which upsets Jan Di because she doesn't consider Yi Jung good enough for her friend. She follows the two around with Jun Pyo by her side, making sure Yi Jung is treating Ga Eul appropriately. At first their plan was successful but because of Jun Pyo's mother, their relationship became strained again.
After their date, Ga Eul finds her self falling for Yi Jung again. Yi Jung feels the same way, but he can't bring himself to admit it, due to his doubt in true love. After a talk with the first girl Yi Jung loved, Ga Eul admits to Yi Jung how she feels about him and asks if he'll go on a real date with her. He rejects her, saying he doesn't date nice girls, foolish girls, or girls connected to his friends. He later changes his mind, and takes her out, though he spends all his time ignoring Ga Eul, and talking to other women. Moreover, Yi Jung takes Ga Eul to his father and tells him to date her. Their date ends with Ga Eul throwing water in Yi Jung's face, but Ga Eul still helps Yi Jung to get safely home when he is too drunk to do it himself.
Other factors keep arising as another member of the group falls in love with Jan Di (which was Yoon Ji Hoo and in a twist of fate, Jun Pyo loses his memory). A girl named Jang Yu Mi who was in the same hospital where Jun Pyo was confined, takes advantage of him to make him fall in love with her. Geum Jan Di never gives up for Jun Pyo to remember his love for her, even reenacting her former acts of defiance. In a last ditch attempt to help Jun Pyo regain his memory, she falls in the swimming pool letting Jun Pyo reminisce his love for her. On Jan Di's graduation, Jun Pyo proposes to her on the cable car at the NamSan Tower where their first date was held. Gu Jun Pyo told Jan Di that he needs to study abroad to fix problems regarding Shinhwa. Jun Pyo asks Jan Di to accompany him as his wife but Jan Di refuses because she has also plans for her future becoming a doctor. The two agreed but Jan Di told Jun Pyo that she will be waiting for 4 years on one condition--if Jun Pyo comes back as a "really amazing man."
The story ends four years later and reveals what happened to the main cast - Yi Jung came back from Sweden where he'd held his art exhibition and visits Ga Eul, who became a kindergarten teacher. Ji Hoo is in the last year of medical school and reopens his Grandfather's clinic. Woo Bin is shown as being happy, but his career is never mentioned in the story. Lastly, Geum Jan Di goes to the beach near the University she was attending, to see Jun Pyo. He then proposes to Jan Di but the answer was still a question among us viewers because when Jan Di was about to answer - Ji Hoo, Yi Jung and Woo Bin arrive saying that they object to the proposal because Jun Pyo and Jan Di didn't ask for their permission first... and they live peacefully.
Please don't get mad if it isn't a good synopsis. Please!