A romantic comedy about a woman who has an aversion for flower boys and a man who has an obsession with appearance as they overcome the prejudices against people with flaws. Joo Seo Yeon is a hot-blooded physical education high school teacher with a strong personality. 365 days and 24 hours, she is wearing her training uniform or jeans and sneakers. Because she suffered hardships due to her handsome older and younger brothers, she hates flower boys. Her ideal type is a “not handsome guy”. She will enter into conflicts with handsome Lee Kang Woo in everything. Lee Kang Woo is the chairman of boards of the high school. He is a man who is incredibly arrogant and is obsessed with appearance. He likes the attention of others and loves his looks. He spends 12 hours of his day to improve his looks. He has a flawless and handsome appearance. However, he has a secret that no one knows: he is suffering from past trauma. 15 years ago, he was overweight and ugly. This was when he got rejected by Seo Yeon. He had to change school after he had acute enteritis in the school bus. While meeting with a well-known psychologist, he realized that his irritable bowel syndrome disorder is connected to that girl of 15 years ago. He became the chairman of the school she is working at. She has changed so much, in the past, she hated ugly men and now hates handsome men.