Choi Ji Won has a disease only her and her family knows about, her disease prevented her from leaving the house since she was born-- her parents afraid of her health if she were to be in contact to the outside. Ji Won's past personal doctors tried finding out what her disease was, but due to her cold attitude and refusal of physical contact, her doctors have given up on helping her and quit. But now her family has decided to hire a young doctor prodigy, a young male named Hwang Minhyun, in hopes that he will be able to stay with her and communicate due to their small .
Although Choi Ji Won has a handsome young doctor in her home, she does not care for romance, she has no time for flirting or physical affection-- her only goal is to befriend him and sneak out with him. She thinks of Minhyun as her ticket to the outside.

Hwang Minhyun sees Ji Won as a snobby rich girl, but as he finally gets to sneak a peek at her unguarded personality, he realizes it wouldn't be so bad to get close the girl. Although his horrible past begins to rehash itself as he notices something similar in Ji Won to his previous patient...
Minhyun tries to examine Ji Won's physical and mental health, but her refusal leads him to a bigger curiosity to her health. She doesn't show how she actually feels, but he starts to notice her weird behavior and careful attitude and begins to analyze them, connecting the dots. But he starts falling in more and more into her appearance and behavior, he forgets he's supposed to look after her and instead brings her to the outside world of her request, and realized he made the biggest mistake on behalf of his new beloved...