“Michael Gregorio” is actually a husband-and-wife team, and this is their second novel. In genre, it is a whodunnit, but a rather special one. The story is set in Prussia in 1807, soon after the battle of Jena and with Prussia under occupation by Napoleon’s armies; and this gives the book much historical interest. The springboard for the whole story is the discovery of three murdered children in a lonely cottage. The children have been both murdered and sexually mutilated, and features of the blood stains in the room suggest dynamics other than “mere” violence. Soon the children’s father is found to have been viciously murdered; and then the smashed and grotesquely flattened corpse of a woman who may be the missing mother is discovered. A tone of gory, perverted horror prevails from the start, and works in startling contrast to the elaborate and formal style of the prose (partly indicative of the period and partly of the personality of the narrator Stiffeniis), with a steady unveiling of dark facts and a cranking-up of tension.