Years after a K-pop star saves her life, a fan learns of his death — but when she's suddenly transported to the past, she sets out to change their fate.

It is a love story of Han Se-gye (Seo Hyun-jin) who is an A-list actress. She is known as a troublemaker and the object of many rumors. Her life is a mystery, but, in reality, she suffers from an unusual phenomenon. At a certain point every month, her appearance changes to a different person. She lives one week out of every month with a different appearance, and Seo Do-jae (Lee Min-ki) who is an executive director of an airline company. He seems perfect with an attractive appearance and intelligence but, he suffers from prosopagnosia. He hides this disability and tries hard to memorize people by their habits and mannerisms. The only face that he is able to recognize is Han Se-gye’s.