It’s about a man who pretends to have amnesia when he’s told he’s going to be killed, and a woman who pretends to be his girlfriend when she’s told she doesn’t have much time left to live. No Go-Jin (Kim Jae-Wook) is the most popular math tutor in the private education sector and the CEO of GOTOP Education. Although he has only a high school education, he has achieved all his success thanks to his exceptional intelligence. He appears to be the perfect man—handsome, with a high IQ, and wealthy. He is also a narcissist. One day, he is suddenly warned that he is going to be murdered. Lee Shin-A (Krystal) works as No Go-Jin’s secretary. She is a diligent and responsible employee. Because of her quiet and introverted personality, she has little presence around her boss, No Go-Jin, and her coworkers, to whom she seems almost invisible. Her coworkers begin to take notice of her because she has worked for the infamous No Go-Jin for over a year. Then she discovers that she doesn’t have much time left to live.