Inspector Henry Cutter and Sergeant Gideon Bliss

It is the winter of 1893, and in London the snow is falling. It is falling as Gideon Bliss seeks shelter in a Soho church, where he finds Angie Tatton lying before the altar. His onetime love is at death's door, murmuring about brightness and black air and about those she calls the Spiriters. In the morning she is gone. The snow is falling as a seamstress climbs onto a ledge above Mayfair, a mysterious message stitched into her own skin.

London, 1894. Inspector Henry Cutter is in an unconvivial temper. Then the murders begin. The first to die is Sir Aneurin Considine, a decorated but long-retired civil servant, is found dead amongst his beloved orchid collection, killed by a wound inflicted with surgical precision. Soon, other victims suffer similar fates. More men in powerful positions; more murders that are gruesome but immaculately orchestrated. Hot on the tails of this invisible adversary are Inspector Cutter, along with his hapless but endlessly enthusiastic sidekick, Sergeant Gideon Bliss.