No relationship is perfect, but Leo and his long time girlfriend probably won the award for the most imperfect. After years of dating normally, it somehow ended up being an unhealthy relationship full of cheating and lies. It wasn't his fault, although it was his forgiving nature that lead him to take her back no matter how many times she hurt him. When Leo has had enough he goes to the roof of their apartment building ready to end it all. Once there, he sees a piano in front of him and suddenly all thoughts of suicide no longer exist. They are replaced with questions: Where did this come from, why does he feel as though it was pulling him in and who is "Wonshik" the name enscribed in the piano? He started playing Wonshik's piano to cope with the pain in his chest. He felt that whomever they were, they would now forever be an important part of his life. He owed him, he owed him his life.