Chaeyoung is a graduating college student while Mina is working at her dad's company. Mina once gets drunk and slept with a guy that she doesn't know who. She has a friend named Nayeon but Mina didn't know that the guy she slept with was Nayeon's younger brother which is Chaeyoung. What Mina and Chaeyoung don't know is that they are already arranged by their parents to marry each other.After seeing each other again, will there be something more interesting that may happen with the both of