In the France of Louis IV, Francine has been scarred by smallpox, and is facing the future as a nun. However, a snowdrift and an accident prevent her arrival at the convent, and staying at an inn she meets the Baron Montaigu. There is a mystery in the Baron's past life, for his wife has died, apparently of poisoning. He persuades Francine to become his wife, with the object of ensuring his first wife's inheritance. Francine is led into deception after deception when she meets first her predecessor's uncle and then her lover. The suspense builds up as the reader's sympathy is roused first on one side, then on another.