What Should I Do?

Not knowing who her parents are and being raised in an orphanage, all she had was her twin brother whom she would die for if need be. Well, now her brother asks her to do something for her saying it's small but she doesn't consider posing as him is small. Especially since he's a newly famous singer who just joined an all boy band with whom he lives with.
Will she be able to pull it off or is she going to crash, burn and ruin her brother's wildest dreams?

WARNING: THERE IS STRONG LANGUAGE.

{Inspired by my favorite Korean Drama You're Beautiful.}