A middle school girl writes a light novel about loving her older brother, wins an award, then watches him publish it under his name instead. The show is honest about what it's really asking: how much of yourself do you pour into a story about wanting someone, and what happens when that story becomes public and he's reading it. The romance between them never quite settles into comfort, because every scene carries the weight of a confession she can't fully take back.

Yū Nagami dreams of becoming a light novel author, but despite entering contest after contest he has never won. When he checks the winners of his latest competition, he finds that a writer called Chikai Towano swept the field, and that the name belongs to his younger sister Suzuka, a gifted third-year middle schooler and student council president. Her winning novel is about a little sister who adores her older brother, and she cannot let anyone know she wrote it. She asks Yū to take her place, and he agrees on one condition: he will play Chikai Towano only until he publishes a book of his own. In the meantime he uses the role to sharpen his writing and to meet other authors and new people. The result is a romantic comedy with ecchi elements, built on a sibling secret.