What happened to her? The truth behind the hidden case is revealed! Music student Yeon-seo heads to Seoul to meet her sister. She's almost there,until she sees her sisters body surrounded by people and policemen. The police clarified her death as suicide and wraps it up. However, Yeon-seo feels there's something more to it then what can be seen and starts digging through the case herself. Detective Kim pays attention and starts reinvestigating the case. The more they dig, the more heartbreaking and shocking news they find...