Lim Sae-mi, a sixteen years old student dreams of becoming a trainee at the top three entertainment industry in Korea, SM Trainee. She is not what you imagine her to be-- for a short person, she is kinda.. overweight. However her dreams were crushed as she was shown by reality what their beauty standards really are. She was about to give up her dreams when an invitation to join SM Pre-Trainee Programme was sent to her house after rescuing a mysterious man on the day she auditioned.