The two big family want them to be united by arranging the merriage of their grandson and granddoughter, but what will happen if both of them are men? Choi Siwon is a nice man. He is in love with his first crush, 'Jessica' Kim. He promises to make her fall for him. Even if, he know that she is carrying a baby from other man. Kim Heechul is Jessica's brother. They like to switch each other. Now, when Jessica was missing, he pretended to be her for his beloved grandpa. J