It is 1863, and as a reluctant Inspector of Vice, Campbell Lawless undertakes a reckoning of London's houses of ill repute, a shadowy netherworld of frayed glamour and double standards, mesmerizing and unspeakable by turns. From the erotic booksellers of Holywell Street to the alleys of Haymarket, he discovers backstreet cast-offs and casualties of the society bordellos, and becomes fascinated by a musician who has established a foundation for fallen women. But his inquiries draw the attention of powerful men, who can be merciless in defending their reputations. Lawless must unlock the heart of a clandestine network, before he too is silenced.