"Ore ga Suki nano wa Imōto dakedo Imōto ja nai" centers around Yuu Nagami, a high school student and aspiring light novel author, who writes under the pen name Chikai Towano. His works focus on imouto (younger sister) themes, a genre he is deeply passionate about. Yuu’s life takes a turn when his younger sister, Suzuka Nagami, discovers his secret career and becomes his primary critic, often mocking his writing. Despite her harsh demeanor, Suzuka is a talented athlete and holds a complex relationship with her brother, oscillating between disdain and subtle care.

The narrative intensifies when a new girl, Minami Asuhina, transfers to Yuu’s school and reveals herself to be a fan of his work. Minami, who writes under the pen name Sakura Irodori, is also a light novel author specializing in imouto stories. She admires Yuu’s writing and seeks to collaborate with him, creating a dynamic where professional rivalry and personal feelings intertwine. As Yuu navigates his relationships with Suzuka and Minami, he faces challenges in balancing his personal life, creative aspirations, and the expectations of his readers.

The story explores themes of sibling dynamics, creative ambition, and the blurred lines between fiction and reality. Yuu’s interactions with Suzuka and Minami often reflect the tropes and conflicts found in his own stories, creating a meta-narrative that comments on the imouto genre itself. The series delves into the complexities of familial bonds, the pressures of artistic expression, and the pursuit of personal and professional growth. Through its characters and their evolving relationships, the manga provides a layered exploration of identity, ambition, and the impact of storytelling on both creators and their audiences.