Konoha Inoue, a high school student leading a double life, conceals his identity as a successful author who penned stories as a young girl. Within the literature club, he crafts impromptu tales for Tooko Amano, a senior student known as the 'book girl' for her peculiar habit of consuming written words. Together, they embark on literary investigations, uncovering mysteries hidden within books. When Chia Takeda solicits their help in composing love letters for her crush, Shuuji Kataoka, a seemingly innocent task evolves into a darker enigma that entangles Konoha in unexpected ways.