Jimin and Seulgi have had feelings for each other since they were children. One day Seulgi's parents told her they would be moving to America to help her achieve her dream of becoming an idol. Without hesitation, she tells Jimin her feelings for him and he returns the gesture. Before leaving to America she made a promise to Jimin; "When I come back, idol or not, let's be together." Years have gone by since that promise and now Seulgi is back in Korea, ready to debut as a member of Red Velvet. As promised, Seulgi is ready to start a relationship with Jimin, but theres one problem; Jimin is now in the biggest K-pop band in history! Will Jimin remember his promise to Seulgi or will she just have to give up on him and remember their promise as some stupid childhood memory? Or is there something more to these lovebirds' story?