She's not pregnant. He's not going to be a father, but one night a mishap leads Oh Sehun to concoct a plan that kills two birds with one stone: saving himself from marriage with his mother's best friend's daughter and buying time to wait for his girlfriend to return from abroad. Plans begin to go awry when his girlfriend's heart changes and Namjoo has already left his home. Sehun ends up scheming to bring Namjoo back into his home only to face turmoil again. A jealous ex and a nosy cousin. Thrown into the mix for chaos is Namjoo's family's background.