Kim Tae-joo is the eldest of three siblings. She is a doctor who is known to be warm-hearted and tolerant, but she also has a hot temper. She cuts off relationships with people whom she doesn’t like. Lee Sang-joon is a popular actor. He is also the eldest sibling in his family. Since he was a child, he has been loved by his family deeply. His family was once in debt, but, after he became successful, he paid off their debt and continues to support them financially. During filming for an acting project, Lee Sang-joon gets injured and goes to the hospital. There he meets his first love Kim Tae-joo, whom he knew when he was an elementary school student.