Toshokan Sensou tells the story of Kasahara Iku, the first woman to join the Library Task Force. In the near future in Japan, the Media Enhancement Law has been forced upon the population censoring all books and media. To counter this, the Library Defense Force was created. To protect themselves against the Media Enhancement Law Commission, all major libraries are fully equipped with a military Task Force, who take it upon themselves to protect the books and freedom of media of the people. This anime follows Iku and her fellow soldiers as they protect various special books and artifacts from the oppression of the Media Enhancement Law Commission. A love story, war story, and comedy all rolled into one.

Kasahara Iku and Dojo Atsushi receive an emergency recall in the middle of their date as Japan is rocked by a terror attack. Their new duty is a protection detail assigned to Touma Kurato, an author. Meanwhile, the relationship between Librarians and the Media Purity Committee is also worsening.

An unaired episode included in the Toshokan Sensou DVD volume 3, and later on Blue-ray Box (June 8, 2012) that celebrates the airing of Toshokan Sensou Movie. Komaki was arrested for the violation of human rights of his girl friend Marie, who had difficulty in hearing. He was kept in custody and tortured by the Media Improvement Forces. The members of the Task Forces made a desperate effort to rescue him.

At Academy Island, everything is settled through "Games" waged for a certain number of stars, with the strongest student being granted the ranking of Seven Stars. Hiroto, a transfer student, unexpectedly beats the strongest empress and becomes the pseudo-strongest in the school! A mind game of lies and bluffs begins!