Toshokan Sensou

The premise of Toshokan Sensō involves the Japanese government passing the Media Betterment Act (MBA) as law in 1989 which allows the censorship of any media deemed to be potentially harmful to Japanese society by deploying agents in the Media Betterment Committee (MBC) with the mandate to go after individuals and organizations that are trying to exercise the act of conducting freedom of expression activities in the media. The conflict between MBC agents and library soldiers has continued to 2019, when the story begins. In accordance with the Japanese era calendar scheme, 1989 in Toshokan Sensō is rendered the first year of the fictional Seika (正化) era, rendering 2019 as Seika 31.

Toshokan Sensō follows the life of Iku Kasahara, a new recruit in the Kantō Library Base who joined in 2019 after being inspired by a high ranking Kantō Library Defense Force member who saved a book she wanted to buy that was targeted for censorship. After joining, however, she finds the pace to be very demanding, and that her drill instructor Atsushi Dojo seems to have it out for her by making it especially difficult for her. On multiple occasions, Kasahara shows herself to be reckless, particularly when she puts Dojo in danger by not securing a criminal in the base's library, and later getting involved with Media Betterment Committee agents despite not being a high enough ranked official; in both instances Dojo has to help her out of trouble. Despite these imperfections, Kasahara is enlisted into the base's Library Task Force, an elite group of soldiers who go through rigorous training in order to respond during difficult operations. This is partially due to Dojo realizing that he did not give Kasahara adequate training, so he gives his recommendation that she join the task force, of which he is a member, in order to correct this mistake on his part. Other recommendations come from the captain of the task force, Ryusuke Genda, and second class task force library officer Mikihisa Komaki who is the same rank as Dojo. Along with Kasahara, another new recruit named Hikaru Tezuka is also enlisted into the task force who is much more capable at the position than Kasahara. Kasahara continues to try her best in the face of difficult challenges while protecting the books she has sworn to protect. The logo of the Library Defense Force.