July, 1858. London swelters, and trouble is brewing. Forensic scientist Adolphus Hatton and his trusty assistant Albert Roumande have a morgue full of cholera victims to attend to, and an eager apprentice to teach. But alongside the cholera outbreak, London is also home to a growing unrest. When a leading politician of the Irish Unionist movement is murdered, the flamboyant Inspector Grey calls on Hatton and Roumande to help solve the case.

But Inspector Grey proves difficult to deal with – callous and hot-headed, he is determined to catch his criminals using any method, no matter how corrupt. When it becomes clear that they are dealing with a series of violent killings, Hatton and Roumande must attempt to find the connection between the victims – at the same time unravelling a bombing campaign by a group of would-be terrorists and exploring the method of fingerprinting, their newest forensic tool.

And amongst all this, Professor Hatton finds himself dangerously distracted by a beautiful woman and painful memories from his past. As the kaleidoscope of outlandish characters, dockside strikes, bomb blasts and violent retribution reaches a crescendo, Hatton’s skills are tested to the limit.