This is the story of Dalessius, an orphan who trains as a calligrapher and who, at the age of 20 and after inadvertently using disappearing ink on a death sentence and being put in prison himself, ends up working for Voltaire. He is chosen, although it's not clear why Voltaire would pick such a young bungler for such a task, to investigate what appears to be a case of judicial murder in Toulouse.
After a series of surreal adventures involving a retired executioner, an automaton, an automaton maker and his beautiful (but cataleptic) daughter and women who have messages written on their bodies, Dalessius uncovers a plot by the White Penitents. With Voltaire directing operations from afar the authorities are alerted, but the ending is not that happy.
The story is written in a limpid style (which was helped by the smooth translation), with the action moving along at a fast pace. However there is also very clever use of language and metaphor. For example, "It was obvious that certain pieces fit together like parts of a sentence, but...I couldn't imagine the grammar that regulated their construction."
The characters were idiosyncratic, and well observed, and I particularly liked Kolm, the helpful, former executioner. However they didn't seem to have much of an inner life, particularly the main protagonist, Dalessius. Consequently, although this was a very enjoyable read, and one that I would certainly recommend, it didn't draw me into Dalessius's world, instead it felt more like being an interested bystander as events unfolded. For me, this was a diversion (and that's not necessarily a bad thing) rather than a deep or realistic novel.