The heroine of the story is Laurence de Cinq-Cygne, a young aristocrat living in the Aube region of France. An elderly aristocratic couple, the d'Hauteserres have come to live with her. Their sons, Robert and Adrien have gone into exile to fight against Napoleon. The story starts in 1803 when Laurence is taking part in a Royalist conspiracy to overthrow Napoleon who is then First Consul. Her cousins the Simeuse twins, and Robert and Adrien d'Hauteserre, who are all exiled aristocrats, return secretly to France to take part in the plot, and she helps to hide them.
However the plot is discovered, and Corentin and Peyrade who are spies working for Police Minister, Joseph Fouché travel to Aube to find the conspirators. Senator Malin, a leading politician who now owns the Simeuse brothers' confiscated property of Gondreville, also travels there to hide evidence of his own dealings with Louis XVIII.