While fleeing Paris, conman La Motte is forced to take under his wing Adeline, on the run from her father, who is trying to force her into becoming a nun.  

Although the effects of scenery on people's moods are important all through the book, the author really goes overboard with the travelogue sections of the third volume, apparently based on travel books of the time. This striving for geographical realism is odd given how unrealistic the people are.