Kanojo ga Koushaku-tei ni Itta Riyuu

Why Raeliana Ended Up at the Duke's Mansion centers on Rinko Hanasaki, a young woman who dies suddenly and awakens as Raeliana McMillan, the eldest daughter of a nouveau-riche baron in the world of a novel she once read. Realizing that she has become a minor character destined for an unhappy end, Raeliana moves quickly to break off her engagement to Lord Francis Brooks, the man originally responsible for her death in her former life. But Francis refuses to let her go, forcing her to seek protection from the only figure with enough power to keep her safe: Duke Noah Wynknight, the story's male protagonist. Armed with knowledge of the novel's plot, Raeliana strikes a bargain with Noah, promising to keep his secrets if he will pretend to be her fiancé. What begins as a calculated attempt to survive soon becomes far more complicated, as the duke shows a side of himself that only emerges around her. Caught between a dangerous former fiancé, a suspicious alliance, and a future she is desperately trying to rewrite, Raeliana must rely on every lie she tells to stay one step ahead of fate.