To fulfill her dying father’s last wish and prevent turmoil among their people, Emilia, the eldest daughter of the Bradley Marquis family, agrees to an arranged marriage with Matthias, the heir of Count Karen. Since Matthias is stationed at the border, she moves to his domain, Vanlogia. Determined to uphold her role as lady of the house, Emilia takes charge of territorial reforms, achieving unexpected success and finding a sense of purpose. However, her life is upended when Matthias finally returns, harboring a secret vow that could change the course of their relationship.