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. By analyzing the bone structure, Lacassagne identifies an unknown dead man as the Parisian civil servant Alphonse Gouffé, who disappeared months ago, and is also able to prove that he was murdered. The murder suspects include Gabrielle Bompard and her lover Michele Eyraudt.