The memory of her boyfriend, Baekhyun from a few years ago has disappeared. When Baekhyun meets her again, he finds out that she has gotten into a memory loss, but still approaches her knowingly. Baekhyun pretends to be a friend, not to shake her memory. But fortunately, she has fallen for him again.

Casey has recently started working for Mama Publishing Co. along with her childhood best friend, Baekhyun. One day, on her way home from work, she finds an injured cat and decides to adopt him. What happens when she wakes up next to a handsome stranger claiming to be her pet cat? What happens when Casey starts noticing there's something weird going on with her work colleagues? Life just got a hell of a lot more complicated!