When the nearby town turns out to put out a fire on the estate of Valpinson, they find the owner, Count Claudieuse, shot to dead. The testimony of a village idiot and other evidences points out to M. de Boiscoran, a neighbor of the Count. Boiscoran refuses to provide an alibi for himself despite the begging of his fiancée, so she goes on a quest to discover the truth.

Émile Gaboriau (1832-1873) was a French writer, novelist, journalist, and a pioneer of detective fiction. He became a secretary to Paul Féval, and after publishing some novels and miscellaneous writings, found his real gift in detective novels. Gaboriau's most famous character was Monsieur Lecoq, a young police officer who was the hero in several of his novels.
He also wrote a long series of novels dealing with the annals of the police court which proved very popular.