Desperate to destroy the boys she blames for her best friend’s death, a young woman makes a dangerous bargain with a conniving sorceress imprisoned beneath her university's campus streets.

Venetia Kent wants revenge. She’s watched the Turnbull Club boys, the golden sons of Great Britain, groomed for power in their university's centuries‑old secret society, walk away clean from what they did to her best friend, Julia. But that’s about to change. Venetia has been promised a magical gift by the keepers of the Night City, a shadowy counterpart to the mortal realm. Venetia seeks a fearsome kind of power, and so is brought to the deepest cell of the City, where a single prisoner has been locked away for centuries: Lady Margaret, a powerful Tudor-era witch, who was taken captive by the City when her own lust for power grew out of control. She has the knowledge and ability Venetia seeks.

But Lady Margaret is not just a teacher. Venetia is captivated by a woman whose hunger and strength of spirit match her own. She is entranced. And the bond between them grows as Lady Margaret leads Venetia further and further into her own darkness. Yet as Venetia becomes more powerful, and disturbingly transformed, she discovers Lady Margaret has an agenda of her own, and that Venetia herself is the key to bringing that dark dream to life.