Cain sends Mary Weather away with her cousin Oscar and his mother, a stern woman who promises to carefully look after her. Cain also promises Mary the tea party in the garden again that he promised her in the last book before they part.
He and Crehador go to see a famous medium, Madame Octavia, whose home is the focus of a web of places purchased by Delilah, in the form of Stonehenge. She is said to be in possession of a doll's head that can make wishes come true for those who possess it. But she has been selling it to those who can afford the price. Is there more than one head? There certainly seems to be. Even Mary Weather sees a woman who owns one on the train that is carrying her and Oscar to safety. And when the head is smashed, inside is the skull of an infant... and then they see more people with the talisman... going to see the Queen! What can Delilah be planning?
Cain has been thrown into the sewers beneath the mansion, where he is found by a scavenger who offers to guide him through the sewers to Hell's Castle... for a price. The man and Cain agree, and the man takes Cain there while Oscar and Mary Weather return to London to try and prevent whatever Delilah is planning using the heads.
Cain, meanwhile, is told by the man leading him that explosives have been placed around the city leading to the Deptford Power Plant, and beneath the twelve Angel statues as well. He wonders what sort of mischief Delilah is planning, and it is revealed as the Angel Statues are blasted apart to reveal magical obelisks within that cast a dark pall over the city. With darkness over London and the power gone, the only light is coming from Hell's Castle... where Alexis plans to call back Augusta's spirit back into a newly-grown, but insane body, and begin a 1000 year reign.
Meanwhile, the traitor grows arrogant and prideful, planning to kill Alexis and take over. When the seer, Madame Octavia, threatens to lock his dual personality away again, he kills her, but she threatens that he will never be free if she is dead. He also kills other members of the organization who object to his actions, only to discover that his hand is trembling.
Finally, Cain must face off against his father, Jizabel, the traitor and those who are helping Alexis in his ultimate goal. But is he truly the one behind it, or is there another evil in the shadows... guiding his hands?
This is the last book in the Earl Cain saga and ends on a sad note, as I had suspected. The traitor is redeemed, and the people of London are saved, and we find out the truth of Delilah: that all the people in it are damaged or broken in some way, and joined in Alexis' scheme to find some sort of power over their broken lives. As in the last book with Jizabel, their sad pasts may make you feel a bit sorry for them, but their pasts don't excuse their sins and crimes in the near past and present.
The ending of the book closes on a mysterious note, just as the series began, with Cain's apparent giving Mary Weather her promised tea party in the garden, where she walks almost every day, remembering the promise that he made to her ten years before. This ending nearly made me cry. It certainly did choke me up a good bit, and it probably will do the same for other readers. I really enjoyed the series, but not as much as the earlier series, the Earl Cain Saga, mainly because this time the focus was all on Delilah instead of other, stand alone mystery stories.