Sophia, the daughter of a knight, is asked by a distant relative, a marquise, to take the place of her brother in a political marriage. For the safety of her brother, she is forced to go to a neighboring country, but her partner, Duke of Julius, soon discovers that she is an impostor. In the midst of this, Sophia notices an assassin who is after the Duke, and she risks her life to protect him and nearly dies. Choose. "Death in peace or life in purgatory". When Sophia wakes up again, she is the "favored princess" of the vampire duke's household, a very special one among them. The knight's daughter changes the destiny of herself and her kingdom under the doting love of the vampire duke! 幼い弟を養い、騎士として身を立てていたソフィアは、実家に連れ戻されて身代わりの花嫁を命じられる。 相手は隣国の名門貴族・ジュリアス公爵で、実は吸血種。 接見の場で刺客から彼をかばい瀕死の傷を負ったソフィアは、不思議な質問と共に彼の血を与えられ、目覚めると、人の身ではなくなっていた!? 尊大で無敵の吸血種公爵と、彼の「寵妃」となったソフィアはかけがえのない二人になっていく。 妖しくも凛々しい寵愛ロマンスファンタジー、ここに開幕。