In this, the third (or fourth, depending on whether you include The Four Rivers) of the Adamsberg series, talismans against the plague begin to appear on the doorways of apartments in Paris. And a man making a living as the town crier in the 14th arondissement (and yes, in the novel it is all made plausible) begins to receive strange missives, incomprehensible at first, but eventually deciphered as omens of the Black Death.
OK - it’s hard to describe this novel without it seeming a bit far-fetched, but it really does seem plausible, and by page 30 you will be fairly engrossed in the story. As always in this series, although the serial murder mystery is fascinating and well plotted, it is the characters that capture most of your interest: Adamsberg, Camille, the town crier, the other ‘regulars’ at the square where the crier does his work, and Danglard as Adamsberg’s foil - Vargas creates 3-dimensional characters that you can actually be interested in.
I’ve enjoyed all of the novels in this series so far, and Have Mercy on us All did not disappoint.