a girl group without training session. She takes the name 'Luna', the stage name of a KTOP trainee of 8 years who left because of her. Ahn Hyo-seop as Ji Noo Ji-nu is a member and the leader of popular boyband 'Jackson' under KTOP. He had a close relationship with Shin Suk-ho who is also the person who created 'Jackson'. Before becoming boyband member, he was a backup dancer but Suk-ho helped him to become a singer. He was going through a state of depression and decided to take medication without Suk-ho knowing. He was dating his fellow labelmate from girl group 'Lucy Girls' named Song-Hee. There is a story that Lee Ji-Young hid, that made Ji-nu believe that the real culprit is him and not Jo Ha-Neul. But both of them are innocent and are victims of Lee Ji-Young's scheming. People around Shin Suk-ho Jung Man-sik as Jang Man-sik Jang Man-sik is a songwriter who has worked with KTOP Entertainment. He has a long friendship with Suk-ho and Min-joo. He likes Min-joo so much that his apartment passcode is Min-joo's Birthday. Ahn Nae-sang as President Byun President Byun is the owner of a music rehearsing studio that is used by 'Entertainer Band/tantara band' located in Hongdae. He used to work at KTOP and was a work-mate of KTOP CEO. After leaving KTOP he decided to become a 'church music' director. He knows Shin Suk-ho since the days he was still at KTOP. He knows the real truth of Jo Ha-neul's brother death, and that's the reason why he decided to leave KTOP because of the feeling of guilt. Members of the band Gong Myung as Kyle / Lee Bang-geul Kyle is a genius musician who studied classic guitar at Juilliard. He decided to quit Juilliard to find a new way. He was scouted by Shin Suk-ho after he saw him performing as an extra guitarist in a random indie-band performance. At first he decided to quit from 'tantara band/Ddandara band" because Ha-neul was an ex-convict, but then he decided to trust Ha-neul. He is the guitarist. Lee Tae-sun as Na Yeon-soo Yun-soo is a humble and polite person who is also a single dad, and had worked as a guitarist at a nightclub. He met Shin Suk-ho in the club and is thankful to Suk-ho for understanding that his guitar is precious for him and only he can use