19th-century Europe, from Turin to Prague to Paris, abounds with the ghastly and the mysterious. Jesuits plot against Freemasons. In Italy, republicans strangle priests with their own intestines. In France, during the Paris Commune, people eat mice, plan bombings and rebellions in the streets, and celebrate Black Masses. Every nation has its own secret service and secret organizations that are plotting against each other, perpetrating conspiracies...