Paris, 1888. With the help of forensic medicine, a sensational criminal case is uncovered. The chief of the Paris Sûreté, Inspector Goron, with the help of Lyon University Professor Lacassagne, is able to solve a capital crime that seemed unsolvable according to the methods of forensic science at the time.
A recent widow has invited a group of family friends to her large and secluded country home. However, what the guests don't know is that the reason they've been assembled is that their host suspects one of them might be her husband's killer and she's intent on uncovering the identity of his murderer.
Abel Hradscheck, the owner of an inn in the Oderbruch country, faces financial ruin. For this state of affairs, Ursula, his wife and former actress, is by no means free of blame.