You Are My Oppa (YAMO) is a Korean reality show in which a Kpop idol group will adopt a younger sister to see what the group members are like around their siblings. It has been four years since their first guesting ended in that particular show, but it seems that Infinite's wounds have yet to heal. When an unexpected (and hardly welcome) challenge knocked on their door, it would reopen scars they have long tried to forget. It has been ten years since Lee Sungjin was orphaned, and one day she gets an email from an entertainment company saying they wanted to cast her in some reality show. As she was a little short on cash, she decided to give it a go. What would happen when these two worlds collide? Would it create more scars that take even more years to heal? Or would it create an entirely new beginning for both Infinite and Lee Sungjin?