"For all intents and purposes, we are still blissfully separated from the mortals, but there have been...complications." When a rise in London's supernatural crime puts Fey society at risk of discovery, the Winter Council turns to an unlikely solution- Avery Hemlock, the changeling they sentenced to 500 Years of Nightmares. Inherently lacking social grace and missing approximately two centuries of world knowledge, Avery must find a way to acclimate and solve the case or lose her probationary freedom. After being left at the altar and dropping out of medical school, Saga Trygg attempts to rekindle her faith in life, humanity, and witchcraft. But when her new neighbor, Avery, accidentally reveals the Fey that have been living among humanity all along, Saga realizes magic is far more than prayers, intention, and candles. Each faced with navigating an unfamiliar world, the two form an unexpected partnership-but shortly into Avery's investigation, they discover the threat might be closer to Saga than either of them imagined, and Avery will do anything to protect the first friend she's had in more than two hundred years.