On a night of crimson lightning, Vesper is offered as a sacrifice, but her dormant dragon's blood awakens. Betrayed and viewed as a plaything for the aristocrats, she shatters her magical restraints, revealing scorching dragon scales. For revenge, she assumes a noble identity and infiltrates the Blackwood family's fortress, where she encounters the cursed Prince Lucien. Plagued by the "Absolute Zero" curse, his body decaying, he shares a tragic fate similar to Vesper's—a victim of his own family.
In a quagmire of power and ancient curses, Vesper and Lucien evolve from a marriage of convenience to becoming each other's sole reliance. Her fiery dragon's breath melts his icy curse, and his deathly will protects her from harm. Together, they uncover the Blackwood family's centuries-old bloody secret: enslaving dragons and extracting their blood through brutal alchemy, using the living artifact "Axle" to sustain the kingdom's false prosperity. Vesper discovers that her own kin and even ancient dragon ancestors were victims of this gruesome sacrifice.
During an all-consuming magical coup, Lucien self-sacrifices, completely liberating the Axle, while Vesper sings the "Requiem of the Final Ember," awakening all imprisoned dragon souls. Ultimately, with Julian's blessing, Vesper and Lucien lead the surviving dragon-kin and oppressed people, aboard the "Final Ember"—a vessel repurposed from ancient alchemical ships—towards an unknown new world. They vow to create a future devoid of oppression and enslavement, a future of freedom and dignity.
