Fina, who is plain compared to her sister referred to as the Holy Maiden, faces harsh treatment in her family's earl household. While working as a military doctor on a perilous battlefield, she encounters Leon, a duke's knight. After saving him from near-death with healing magic, she is later proposed for marriage! Despite doubting if he's mistaken her for her sister, Fina finds herself leading a blissful life in the duke's household, contrasting starkly with her own family's mistreatment!