In a small Parisian square, the ancient tradition of the town crier continues into modern times. The self-appointed crier, Joss Le Guern, reads out the daily news, snippets of gossip, and lately, ominous messages--placed in his handmade wooden message box by an anonymous source--that warn of an imminent onset of the bubonic plague.

Concerned, Le Guern brings the puzzling notes to the bumbling but brilliant Chief Inspector Jean-Baptiste Adamsberg and his straight-edged, right-hand man, Adrien Danglard. When strange signs that were historically believed to ward off the black death start to appear on the doors of several buildings, Adamsberg takes notice and suspects a connection with Le Guern's warnings. After a flea-bitten corpse with plague-like symptoms is found in one of the marked buildings, Fred Vargas's inimitable genius chief inspector is under pressure to solve the mystery and restore calm to a panicked Paris. But is it a real case of the bubonic scourge, or just a sinister trick designed to frighten as the body count grows and the culprit continues to elude the police?

Peopled with charming and eccentric Gallic characters, and packed with gripping historical detail, Have Mercy on Us All is a complex, surprising, and stylish tale from France's finest mystery writer.