Tess Grey crosses the ocean in search of her brother, and in London during the reign of Queen Victoria, she discovers the Lower World, where vampires, powerful sorcerers, werewolves and other creatures roam the streets. A letter from her brother turns out to be a trap, and the girl is kidnapped by the Dark Sisters from the secret organization "Curse Club", who use her supernatural ability to turn into any person, recognizing other people's thoughts and feelings. Rescued from captivity by the Shadowhunter, Tess is caught in a network of insidious intriguers and realizes with horror that a mortal danger hangs over all the Nephilim. The girl faces a difficult choice - to find and free her brother or, together with the Twilight Hunters, to enter the battle for the salvation of the world. In this way, Tess has to understand that love is more dangerous than the most terrible witchcraft.