Jisung and Soa have been friends since childhood. Jisung has always been there for her, taking care and protecting her even at such fragile age. Soa only had her mother, but one day she decides to take her life, leaving Soa by herself. That's when her aunt appears in the image and has to take her niece in America, where she lives and works. Soa doesn't want to leave for one simple reason. Jisung. She made a promise to him, that she will forever stay by his side no matter what. Unfortunately, she has to break that promise, which will leave Jisung devastated. But she promises she'll be back. Years later, at the age of sixteen, Soa returns to Korea. She starts high school there and meets Jisung again, after eight years she's been away from him, only to find out Jisung changed. A lot. He's definetly not the boy Soa knew. Not the boy that used to take care and protect her. Will Jisung be able to accept Soa back? Will Soa accept Jisung's life now or will she try to change him?