A disgraced socialite who had fled to California is found barefoot in a snowy New York alleyway. There is no sign of how she got there, and she is too traumatised to speak. The only clue is a note found scribbled in the Bible she is clutching.

The Arcane Society appears to be responsible – but no one knows anything about them. Newly qualified doctor Clara Mendel joins the city’s Sabel Club, a once thriving social society now devoted to solving the riddle of Viola Blackman. Clara is determined to help Viola speak again, but she also has an ulterior motive: if she can solve the mysterious case, it may tempt out of the shadows her old sparring partner James Moriarty: nemesis of the legendary Sherlock Holmes.

But as the Sabel Club comes under violent attack, Clara is forced to ask herself to what lengths will the Arcane Society go in order to preserve their anonymity. And how much trust can she truly place in a master criminal?