"Monstar" depicts the lives of ordinary teens who are injured psychologically and heal themselves through the power of music. Yoon Sul-Chan (Yong Joon-Hyung) is the vocalist for the group "Man in Black". He carries deep wounds within his mind, but doesn't express his feelings. Because of his hot temper, he causes trouble. His management company then orders him to carry himself as an ideal student. He joins a music band at school, while facing unexpected events.