On the battlefields of the American Revolution, Matthew de Clermont meets Marcus MacNeil, a young surgeon from Massachusetts, during a moment of political awakening when it seems that the world is on the brink of a brighter future. When Matthew offers him a chance at immortality and a new life free from the restraints of his puritanical upbringing, Marcus seizes the opportunity to become a vampire. But his transformation is not an easy one, and the ancient traditions and responsibilities of the de Clermont family clash with Marcus' deeply held beliefs in liberty, equality and brotherhood. Fast-forward to contemporary Paris, where Phoebe Taylor --- the young employee at Sotheby's for whom Marcus has fallen --- is about to embark on her own journey to immortality.

In this conclusion to the All Souls Trilogy, Diana Bishop and Matthew Clairmont are back in the present and about to face their worst nightmares in the form of their families. There’s still resistance to their marriage, the issues with the Congregation have yet to be resolved, and --- to add to their list of problems --- a long-abandoned son of Matthew’s begins reigning terror on the de Clermont family and the public at large.

This sequel to A DISCOVERY OF WITCHES plunges Diana Bishop and Matthew Clairmont into Elizabethan London, a world of spies, subterfuge, and a coterie of Matthew’s old friends. Here, Diana must locate a witch to tutor her in magic, Matthew is forced to confront a past he thought he had put to rest, and the mystery of Ashmole 782 deepens.

Diana Bishop, a young scholar and the descendant of witches, discovers a long-lost alchemical manuscript deep in Oxford's Bodleian Library. Its reappearance summons a fantastical underworld, which she navigates with her leading man, vampire geneticist Matthew Clairmont.