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!