Three children are massacred in their beds. The crushed corpse of their mother is discovered in a dockside warehouse. Hanno Stiffeniis, a Prussian magistrate, goes to investigate, but everything begins to unwind. Serge Lavedrine, a criminologist attached to the invading French army, steps in to resolve the mystery, and Stiffeniis is packed off to collect the husband from a remote fortress on the Russian border. But the husband, Bruno Gottewald, is dead and buried - killed while out on field manoeuvres. In less than a week the entire Gottewald family has been wiped off the face of the earth. A tragic coincidence? A military conspiracy involving Prussian troops? Or are the French using the massacre to expand their power?