Kim Joonmyeon wakes up with a memory of her leaving yesterday. Holding on to this sad picture, he tries to make his life work again. Yet he was fake and lifeless. How to live when his bestfriend, who is a big part of his life, already left him? But oh well, she was no longer his bestfriend anymore. Joonmyeon felt betrayed and he hated her for doing that. Little did he know, Joonmyeon had missed a tiny but important information. 'How' did Jung Bo-Yun left him, to be exact? SHE WILL SHOW HIM HOW.