"The Haunting of Alaizabel Cray" takes place in a fictionalized London, probably in the late 1800s. After an attack on London known as the Vernichtung, London is overrun with wych-kin. Thaniel and Cathaline, two wych-hunters, encounter a girl named Alaizabel. She seems virtuous, but she is somehow connected with a plot to destroy the world. As the novel progresses, Thaniel and Alaizabel fall in love, thwart the plot of the Fraternity, and discover the origin of the wych-kin.

Thaniel is a talented wych-hunter, following in the footsteps of his famous father. Her father however is lonely even though he shares his house with his wych-hunter partner, Cathaline. While out hunting one night, Thaniel encounters a deranged young woman, Alaizabel Cray. She remembers nothing about her past and Thaniel is attracted by her beauty and vulnerability. She has a strange tentacled tattoo at the base of her spine.

The spirit of a powerful wych named Thatch possesses Alaizabel. This witch is part of a plot to resurrect gods called Glau Meska and start a new world. Orchestrating the plot is a group known as the Fraternity, composed of wealthy and powerful members of society, along with other useful individuals such as policemen, civil servants, secretaries, and postmen. Dr. Pyke and Inspector Maycraft are important members of the Fraternity.

Stitch-face is a serial killer who plagues London. The Fraternity copy his techniques to cover up a series of murders. When these murders are plotted on a map, they match the tattoo of the tentacled chackh'morg on Alaizabel's spine.

Thaniel, Cathaline, and Alaizabel are joined by Detective Carver, Lord Crott, a Beggar Lord, along with some of Crott's men, in a dramatic struggle to thwart the plot of the Fraternity. The ultimate demise of the Fraternity takes place in a once-hidden cathedral in London's Old Quarter. Thatch is killed right at the moment when she is about to summon the Glau Meska. Dr. Pyke reveals that the wych-kin were actually created by mankind, in response to the helplessness and despair brought about by the Age of Reason. If man has nothing to believe in, no greater power, then he must take the guilt upon himself. That guilt comes in the form of wych-kin.

After the Darkness, survivors are grateful for their second chance.

"The Haunting of Alaizabel Cray" was written by Chris Wooding. Born in Leicestershire, England, in 1977, he is known as a writer of fantasy and science fiction. "The Haunting of Alaizabel Cray" won an American Library Association Best Book of the Year Award, among others.