Eia is the last princess of the kingdom of Culva. Born on the night of a lunar eclipse with hair the color of blood, she was dubbed a "Child of the Underworld," and discarded from the palace immediately after birth. 19 years later, she lives in the forest with her flock of falcons. That is, until a knight named Ardelu shows up, claims he conquered Culva, and asks for her hand in marriage. Ardelu would've been an average knight, if not for the fact that he slaughtered Culva's royal family and became known as the "Tyrannical Emperor." To legitimize himself as the legal ruler of Culva, he needs Eia's royal lineage. However, she doesn't see him as a killer, and she thinks his magic is beautiful. Eia believes he's nothing like the cruel person she was told he is, and she's nothing like the princess he expected. In fact, her strength and purity gradually begins to attract him. This is a fantasy romance about a marriage of convenience between two people who never knew love.