During the 31st year of Seika, the battle between the Library Force and the Media Improvement Committee reached a new level of violence. Each group has armed itself for either the freedom of expression or the "protection" of society from the bad influences of media.
Kasahara Iku joins the Library Force with the intent of finding her "Prince" who helped her during a censorship exercise by the Media Improvement Committee and with her strong will of protecting books.