​Seung-woo, who is a 20-year veteran rock musician, forms a band named ‘The Monotones’. But the first vocal’s skill was below standard, and the second vocal has been cast in a new soap opera. Finally they meet the third vocal, Sae-young. But Sae-young leaves the band, because his personality is not compatible with Seung-woo. The remaining members try to find a new vocal, but it is hard to find a good vocal at that time. Seung-woo decides to perform without vocal. It is his last effort to keep the band ‘The Monotones’. Through The Monotones’ rooftop concert without vocal, they come to realize that this is where they should be, and they remember when they first began.