In a near-future Japan, the government has passed the Media Betterment Act, a strict censorship law that allows a paramilitary force known as the Betterment Squad to seize and destroy any published material deemed harmful. In response, libraries have banded together to form the Library Defense Force, an armed organization dedicated to protecting freedom of speech and the right to read. This television special is set approximately six months before the events of the film Library Wars: The Last Mission, and it focuses on the daily lives, romantic tensions, and personal struggles of the Defense Force members rather than the larger war story.

The story centers on Iku Kasahara, a young woman who joined the elite Task Force of the Kanto Area Library Defense Force driven by a childhood memory. Years ago, a mysterious officer, whom she calls her prince, rescued a book from being confiscated by the Betterment Squad. Although she cannot remember his face, she has dedicated her life to finding him. Now a member of the Task Force, she endures brutal training and constant criticism from her stern instructor, Atsushi Dojo, with whom she constantly clashes.

While Iku struggles to reconcile her romanticized memory of her prince with her antagonistic feelings toward Dojo, several other personal dramas unfold. Iku befriends Marie Nakazawa, a Deaf high school student who is a childhood friend of senior Task Force officer Mikihisa Komaki. Marie visits the library frequently, harboring secret romantic feelings for Komaki, who kindly recommends books to her. Their quiet relationship is shattered when the Betterment Squad arrests Komaki on dubious grounds, claiming that a book he recommended to Marie is unsuitable for a person with a disability.

Meanwhile, another Task Force member, Hikaru Tezuka, finds himself jealous when he sees his colleague Asako Shibasaki frequently meeting with a handsome museum curator named Shuji Asahina. Asako appears to be growing closer to the charming curator, leaving Tezuka unsure of his own feelings or the man's true intentions. Adding to the chaos, Iku receives an unexpected visit from her parents, who strongly disapproved of her joining the military. She must frantically hide the fact that her job involves armed combat, leading to complications in her personal life. As Komaki remains in custody and confusion engulfs the unit, the members of the Library Defense Force must rally together, forcing Dojo to make a fateful decision about his team’s future as Iku races to figure out how to save her friends.