Woo-ri is a 29-year-old woman who has lived a straight life guided by her strict grandmother. She dreams of being a writer. Although she adheres to premarital purity, she is in a two-year relationship with Kang-jae, who is more than understanding. However, after visiting her ob-gyn, she finds herself artificially inseminated and pregnant! Her dreams and ambitions get turned upside down, especially marrying Kang-jae. What's worse is that the biological father of Woo-ri's baby is Raphael. The first man she ever kissed. Raphael is the CEO of Diamond Cosmetics and is married to Lee Ma-ri, whom he doesn't love. He longs to find his soulmate. How will this upside-down situation turn out?