Final entry in Brennan's historical fantasy series (A Star Shall Fall, 2010, etc.) wherein the Onyx Court, realm of the fae, lies hidden below Queen Victoria's London.
Few humans believe in fairies, and fewer still know the Onyx Court even exists. And with a technological revolution in full swing, London is threaded with iron: paved-over rivers, pipes, bridges, the tracks of the underground railways. The presence of so much iron is destroying the fairy realm; what remains holds together only by the magic and indomitable willpower of its queen, Lune. Her bewildered experts are researching, by scientific, alchemical and magical means, ways to preserve the court, although most others are resigned to fleeing. Meanwhile, Nadrett, the fiendish gangster lord of the Goblin Market, pursues his own nefarious plans, while, in a connected development, certain prominent citizens, both fae and human, find odd chunks of their memories have inexplicably gone missing. On the streets of London above, Eliza O'Malley searches grimly for her sweetheart, who vanished seven years ago, stolen away by the faeries of the Goblin Market. Of course, nobody believes her when she insists he was stolen by fairies. Only Eliza's unshakeable determination keeps her quest alive. Eventually she will cross paths with Dead Rick, Nadrett's tortured, shape-shifting slave, held in thrall by the memories Nadrett stole from him. This time, Brennan's grasp of period detail is sure, as the Dickensian squalor of most mortal sections of the city has its mirror in the teeming desperation of the Goblin Market. Despite the cast of thousands, many of the characters have real presence, and after a slow start the plot coheres and swirls forward into a series of tense and surprising conclusions.
An absorbing finale to a series that has grown richer with every installment.