Ryeowook have a older sister who really love him. Her name is Cheonsa. For her entire life, Cheonsa take care and spoiled Ryeowook so much. One day, nightmare for losing her sister come into Ryeowook's life and Cheonsa know really well what is bothering her brother so much. She make sure, nightmare is coming because he have done too much activity all day, and Ryeowook believe it until the nightmare really happening in reality.

The world has changed for Ryeowook when her sister leave him. No happiness all his days. No smile all his days. He refuse to go to school. He refuse to talk. He refuse to do anything. 

after a year, Ryeowook decide to back to school. He don't want to disappointing his sister who already live in heaven. And when he back to school, He meet someone who really simillar with his sister. not only with her face but the gaze from his eyes that make Ryeowook really familiar. But, will the boy treat Ryeowook the same like his sister did?