A week before their highschool graduation, the whole class were asked by their homeroom teacher what they want to be when they grow up and write it on a piece of paper; most of the students wrote the profession they want to achieve while others simply wrote how much they want to be wealthy. The teacher released a heavy sigh reading all the classic answers from her students, until she received the last four pieces of papers by the class known bestfriends: Irene, Krystal, Amber and Wendy.

  Karina is not sure anymore if it is her welfare, her Irene unnie is concern with, or she's just not really over with her ex, Junmyeon. For her to know, with her boyfriend Jeno, they started to 'investigate the past' only to discover that Irene's hate towards Junmyeon, is not just because of some childish puppy love after all.