No Go Jin is the most popular math instructor in the private education sector and the CEO of GOTOP Education. Even though he only has a high school education, he has achieved all his success due to his extreme intelligence. He seems like a perfect man, with an attractive appearance, a high IQ, and wealth. He is also narcissistic. One day, he is suddenly warned that he will be killed. Lee Shin A works as No Go Jin's secretary. She is a hardworking and responsible employee. Due to her calm and introverted personality, she has a low profile in front of her boss, No Go Jin, and her coworkers. Her colleagues begin to recognize her since she has worked for the notorious No Go Jin for over a year. Then she learns that she doesn't have much time left to live.