Be My Boyfriend, a spin-off of the popular web series, Best Mistake, depicts the story of Lee Seung Min, a boy with zero presence who is offered a contract relationship by Oh Ji Na, the best girl-crush idol trainee in the school.

Shin Hyeon-seung, Lee Si-woo, Choi Yu-ju, Lim Sung-kyun, Kim Byeong-kwan, Jung Bo-min