BTS is the most popular group in Korea, but did you know they had a secret writer? BTS is known for writing and composing all of their songs... but what happens when the eighth extra memeber, who no ones ever seen on stage, goes missing. They have to replace him. BTS turns to a girl who is on the verge of losing her job, the eighth memeber chose her after all. He knows that she has the potential to write songs for this amazing group. But will they see the potential in her?