Oh Sae Yeon, a young 22 year old woman in America is an incredibly talented psychiatrist who works in one of the famous mental institutions in America. Living in New York with her younger brother, Oh Se Hun, she truly loves her job and is known by her colleagues for being a very approachable and friendly doctor to the patients at Presbyterian University Hospital of Columbia and Cornell while her brother is working as a police officer in New York City Police Department (NYPD). Sae Yeon initially went to America in order to further her studies but she recieved an opportunity to become a doctor here thus she decided to stay here and she never once regretted it. Somehow her brother ended up tagging along with her and worked hard to become a police officer. 

Life was great for her and Sehun. But what's this? Sae Yeon has been given a special patient. She has to travel back to her homeland, South Korea, to meet him. Do Kyungsoo was his name. A 22 year old man with doe eyes which are able to take any woman's breath away and heart-shaped lips which perfectly suit his beautifully carved face. Despite being 22 years old, he acts like a kid to which Sae Yeon found it rather amusing since it strangely fit with his kid-like face. But of course, there is more than meets the eye. Why couldn't any doctor crack him for the past few years? What is his story?