In an alternate timeline, Japan's Taisho era lasted until 1936 instead of ending in 1926. During this time, Tsugumi Kuze agrees to an arranged marriage to save her family's honor, but before following through, her brother commits suicide by fire while holding an old book. Before she can make sense of this tragedy, the Imperial Library Information Assets Management Bureau appears and informs her of books called Maremono, which exert a great influence on those who read it.