In a world where humans maintain peace with vampires through royal tributes, Princess Elias disguises herself as the crown prince and offers herself to the feared Vampire King Noctis to save her younger sister. She soon discovers that her rare bloodline can suppress the king's ancient curse, drawing the two closer despite court conspiracies, betrayal, and deadly enemies. As Elias's true identity is revealed, she and Noctis join forces to uncover the truth behind a thousand-year-old curse, defeat the dark forces threatening both kingdoms, abolish the tribute system, and forge a love that unites humans and vampires.