France 1848: Pietro Maroy is jailed under the accusation of having killed his uncle, Dr. Maroy. Pietro's wife and daughter, 20 years later, obtain a revision of the trial but the young officer in charge of the investigations soon finds himself involved in a mystery... Documents have been stolen, a woman had a prominent role in the murder and a child was abandoned - the night of the crime - in a cab... Discovering not only the real criminals but a lot about his own past, the officer marries Pietro's daughter