Konoha Inoue lives out his days as a normal high schooler, hiding his dark past as a best-selling author who wrote under the guise of a 14-year-old girl. A member of the literature club, he writes improv stories that serve as snacks for third-year student Tooko Amano, the only other member of the club and a self-styled "book girl" who literally eats written words. Konoha is forced to tag along with Tooko as she seeks out strange, literature-filled cases to investigate.

One day, the book club receives a request from Chia Takeda, who asks them to help her write love letters to her crush Shuuji Kataoka. What appears to be a simple request for love advice soon turns into something more sinister when Konoha delves deeper into the matter.