Office worker Satou Konoha dies in an accident and is reborn as a character from a story she wrote as a student—The Dark History. Instead of reincarnating as the heroine as she'd hoped, she's the hated little sister, Iana. And, according to the story, she's destined to perish early on at the hands of her butler! There's only one way to survive—remember the plot of the story and avoid her fate!

To save Konoha from the monster that kidnaps her, Iana triggers her own death flag. With help from Sol, Ginoford, and the others, Konoha's rescue succeeds. Iana barely has time to relax before an invitation to a ball arrives from the capital—the very ball that's the setting for chapter 3 of The Dark History. If Konoha dances with the prince at the ball, it will lead to a death flag for Iana!

As Iana grows used to life in the world she's been reincarnated into, a young man comes to visit—her childhood friend Yomi, back from studying abroad. When Iana remembers Yomi, a character she created, she is left aghast. His role in the novel is to kill Konoha. If he acts according to the story, it will lead to Iana's death. Iana tries to convince Yomi to stop, but it only makes things worse.