It is the love story of Han Se-gye (Seo Hyun-jin), who is an A-list actress. She is known for causing trouble, and there are many rumors about her. Her life is a mystery, but in reality, she has a strange problem. At the same time every month, she looks like a different person. She lives one week out of every month with a different look, and Seo Do-jae, played by Lee Min-ki, is an executive director at an airline company. He looks great and is smart, but he can't recognize faces because he has prosopagnosia. He hides his disability and works hard to remember people's habits and ways of doing things. Han Se-face gye's is the only one he can remember.