To save her dying border village from the creeping blight of the Cinder Rot, twenty-year-old huntress Elysia Vane steps forward to take her cousin's place in the ancient Blood-Tithe—crossing the forbidden Obsidian Bridge as a hostage-bride to Caspian Morvane, the ruthless Shadow King of Noctis. Armed with a concealed star-iron dagger and a dormant birthright of forbidden Starlight fire in her veins, Elysia expects a monster on a throne of iron thorns. Instead, she discovers a besieged mountain kingdom, a winged black dragon named Vaelen, and a brooding immortal king who needs her bloodline tounlock the shattered pieces of the Heart-Ember before both realms freeze into ash. Bound together by a searing blood-bargain on their wrists, fierce enemies become reluctant allies—and soon, an all-consuming passion threatens to burn down every wall between them.