They were two inseparable friends. They had to do everything together. 

Wonwoo and Seokmin got married on the same day and also lived in the same house. 

One year later on a very romantic occasion, they decide it's time to surprise Mingyu and Minghao. 

Yet it's just that this surprise was very uncalled for. No one would have expected an evil Jihoon, fear-filled Seungcheol, and crybaby Jun. 

All the while Jisoo and Dino were being sweet people and celebrating this wonderful day.

A day where the romance between Wonwoo and Seokmin became more than the romance with the one they loved second. 

"Because you're my friend, and the number one in my heart."