This is all about a young, fine man, Kim Geunsook, started to worry about his monochrome world. Have the best & youngest doctor title at Seoul, very good in income, handsome, what could be more wrong about him. But then suddenly his life started to change. When his parents wanted to settle an engagement with their old relative. But what made him shocked was the truth that he will marry an idol from  a well-known girl group! And they even will live in the same roof before they married yet! For worse fact, his future wifey even already have a boyfriend! To hide things, Park Chorong and Kim Geunsook settled up a deal. How will this weird engagement end-up? Will they just keep on going with the marriege, or .... stop it?