High school student Eun Gyeol (Ryeo Un) has hearing-impaired parents, but he has a gift for music. He is a model student by day and plays the guitar in a band at night. One day, he visits a mysterious musical instruments store and travels to a strange place. There, Eun Gyeol meets Ha Yi-Chan (Choi Hyun-Wook), Choi Se-Kyung (Seol In-A) and Yoon Chung-A (Shin Eun-Soo). They form a band called Watermelon Sugar. Meanwhile,Ha Yi-Chann has a crush on Choi Se-Kyung, who is known as the Cello Goddess of Seowon Arts High School, and tries to win her heart. Yoon Chung-A is hearing-impaired. She is cold and aloof to others.