Jang Geu Rim is a young girl who dreamed of becoming a pop singer and attending an arts high school. As a child, she had been ill with cancer. It was the top star Tae Joon that helped her get through. She's a huge fan of him and she has a little crush on him also. Tae Joon also attends the art high school that Jang Geu Rim is going to attend. Like most of the girls in the school, she really liked him as a fan but he put all his attention on the pretty CF star Irene.
Irene is actually our male lead. Hyun Woo is the person who is cross dressing as a girl to attend this art school. He wanted to debut in a boy group but has to acquire skills and have a better performance to be added to the group. So using his fake identity of Irene, who is a pretty female CF star and also the country's younger sister, he attends the art high school in hopes of acquiring more skills and debuting. Unfortunately for him, he could not have his own room and it just so happened that Jang Geu Rim is his roommate. The two did not get along well at first. Since Hyun Woo never talked (to hide his voice) and tried to distance himself from Jang Geu Rim so that she wouldn't find out, she thought that "Irene" was snobby. He thought that Jang Geu Rim was slightly annoying. It was inconvenient for him because he had to sneak out without her knowing to go to the dance studio to practice and he also had to wear a wig at all times (including while sleeping).
During this time, Jang Geu Rim befriends Tae Joon who just wants her to find out what Irene likes and what her hobbies are. However, after a while, when Hyun Woo had a fever, his wig came off. That was when Jang Geu Rim found out that he was a boy. She decided to keep his secret under certain conditions of how they were to dorm together. They got closer and developed feelings, unknowingly. Tae Joon also, unknowingly, began to develop feelings for Jang Geu Rim. Hyun Woo falls for Jang Geu Rim and and Jang Geu Rim was also beginning to fall for Hyun Woo. It was really cute watching her try to keep his identity a secret, deal with Tae Joon, and also have to deal with the three girl fans of Tae Joon and the three boy fans of Irene. She also taught him to have fun during practice and how to express more freely. As they learn from one another and fall in love, he strives toward his dream of debuting and not giving up Jang Geu Rim.