Kedamono no Uta

This world is filled with MONSTERS. In any epoch, in any place, in any person... Yui found her classmate Kotoha badly beaten up in abandoned hospital. After recovery Kotoha becomes sticky to Yui. According to Kotoha, she can't remember a criminal's face, but if she return to scene of crime, there is a chance that she may recall something. So in order to find criminal and stop rumors saying that Kotoha herself set it up from spreading, Yui decides to bring Kotoha back to that hospital.