A sweeping Gothic romance of immortality, transformation, and the covenant between the living and the dead.
Yorkshire, 1812. Lucien Varenne is no ordinary French migr . He is among the first vampires ever made - three thousand years old, bound by duty to the Crimson Court, and sent to England on a mission that should be routine: confirm whether a village governess carries the bloodline of the witches who created his kind. If she does, the First Law is clear. She must be eliminated.
Eliza Caven has spent twenty-seven years learning not to notice the strange things that happen around her - gardens that bloom out of season, sick animals that recover under her hands, the unsettling accuracy of her intuition. She has made herself small, practical, unremarkable. But when the precise, unsettling Monsieur Varenne appears on the moor road, she recognizes something in him that she has spent a lifetime recognizing in herself: a person hiding extraordinary truth beneath ordinary manners.
Their cautious courtship unfolds across a Yorkshire autumn - two people trained in secrecy learning to be seen. But when Eliza discovers her mother's hidden writings and Lucien reveals the full history of the ancient covenant between vampires and witches, the stakes become mortal. The Crimson Court will not tolerate any threat to their sovereignty. And the connection growing between Lucien and Eliza is becoming something the world has not seen in three millennia: the Crystalline, a transformation that exchanges their natures and makes possible what neither thought they could have.
Fleeing to France, they find refuge among the Covenant Keepers - vampires who have preserved the memory of their original purpose. Here Eliza learns she is the prophesied velhari, destined to stand at the boundary between life and death and restore what was broken. But the Court's enforcer is hunting them, Lucien's mortality is advancing faster than either anticipated, and the ancient laws that governed their kinds for millennia will not be easily rewritten.
Spanning forty years and two continents, Eclipse of the Mortal Heart is a story of love across impossible boundaries, the cost of transformation, and the long work of building something new from the ruins of the old. For readers of The Invisible Life of Addie LaRue, The Historian, and Outlander - a Gothic romance where the monster learns what it means to be human, and the woman who sees everything finally learns what she is capable of becoming.