"Library War: Spitfire!" is a spin-off manga series set in the same universe as the original "Library War" by Hiro Arikawa and illustrated by Kiiro Yumi. The story is set in a near-future Japan where the government enacts the Media Betterment Act, allowing censorship of media deemed harmful. In response, libraries establish the Library Defense Force (LDF) to protect intellectual freedom and oppose censorship. The narrative focuses on the LDF's elite tactical squad, known as the Spitfire Team, which specializes in high-stakes missions to safeguard books and information.

The protagonist, Mikihisa Komaki, is a skilled and determined member of the Spitfire Team. Komaki is driven by a strong sense of justice and a personal connection to the cause, having witnessed the impact of censorship firsthand. Alongside Komaki, the team includes other key members such as Shibasaki, a sharp and resourceful strategist, and Dojo, a seasoned veteran with a calm demeanor. Together, they navigate complex missions that often involve confrontations with the Media Betterment Committee (MBC), the government agency tasked with enforcing censorship.

The plot revolves around the Spitfire Team's efforts to protect libraries and their collections from MBC raids, often involving high-tension standoffs and tactical operations. The series delves into the moral and ethical dilemmas surrounding censorship, intellectual freedom, and the role of libraries as guardians of knowledge. It also explores the personal lives and motivations of the team members, adding depth to their characters and highlighting the human cost of their mission.

Throughout the series, the Spitfire Team faces various challenges, including internal conflicts, external threats, and the ever-present tension between upholding the law and fighting for what they believe is right. The narrative balances action-packed sequences with moments of introspection, creating a compelling story that underscores the importance of preserving freedom of thought and expression.