Kim Seo-Jin (Shin Sung-Rok) is a man who is driven only to achieve success in his life. Thanks to his efforts, he is the youngest executive at his company. His life is perfect, with his beautiful violinist wife Kang Hyun-Chae (Nam Gyu-Ri) and a daughter. His wonderful life comes to a halt when his young daughter is kidnapped. He falls deep into despair. To change the past, when his daughter was kidnapped, he contacts Han Ae-Ri (Lee Se-Young) approximately one month in the past. Han Ae-Ri has busy days with her studies and working a part-time job to make enough money to pay for her sick mother's operation. One day, her mother suddenly goes missing. Han Ae-Ri falls into despair, when Kim Seo-Jin from the future contacts her.

The story is about a boy, Lee Sin, who is popular in his High school for his band team- "The Stupid", and a girl, Lee Gyo Won, from the same institution, who is devoted to traditional Korean music. Lee Sin's father, Lee Hyun Soo was a popular guitarist during his time but is now in the verge of death because of drug addiction; which was also the cause of his separation with Song Ji Yeong (Lee Sin's mother) a long time ago. The female lead, Lee Gyo Won's grandfather, Lee Dong-jin is one of the top 3 traditional musicians of his age and his biggest wish is to see his granddaughter become a traditional music prodigy. He is strictly against modern music because he believes that it misleads the tradition. The high school comes up with "The 100th Year Anniversary" where students get the opportunity to show their skill. Now, will Lee Sin be able to prove his skill in modern music like his father did? And will Lee Gyo Won be able to keep up her grandfather's expectations? Or something else is...