In the Kingdom of Acacia, royalty are born with blonde hair, silver hair, blue eyes, etc. Everyone is born gorgeous and good-looking. The third princess, Caroline, who was born with chestnut hair and ink-blue eyes in such a beautiful kingdom, has lived her whole life in a detached palace because her family hates her as a “plain princess.” Her family forced her to work every day, and her younger sister used her as an outlet for her stress. One day, she receives a summons from her father and rushes to the audience chamber, where she finds Reinhard, the crown prince of Tuscarna, a kingdom inhabited by beastkin. He also has snow-white ears and a tail, and suddenly asks her to marry him, claiming that they are “destined mates."