Liu Huijing (Park Shin Hye) was once a female gangster that everyone feared. She was good at fighting and was once imprisoned for committing a crime. However, prison would be a new starting point to change the trajectory of her life. In prison, she realized the mistakes of her original life, and she decided to change her past. So, after being released from prison, she decided to work hard and become a female doctor respected by everyone. And this wish was realized after hundreds of days of reading books. However, as a female doctor, Huijing will face more difficult challenges.