Yuu Nagami, an aspiring light novel writer, faces a string of rejections in writing contests, yet he persists in his quest for improvement. After a competition where a mysterious author named Chikai Towano triumphs, Yuu is shocked to discover that Chikai Towano is his unlikely sister, Suzuka. Unable to reveal her secret, Suzuka enlists Yuu to masquerade as Chikai Towano until he achieves literary success himself. Embracing this dual identity, Yuu navigates the world of authors, honing his craft and building new relationships as he strives to fulfill his sister's request and realize his own writing dreams.