The book concerns the eponymous character, who begins as a poor country girl who is forced by poverty to leave her village home and go to town. There, she is tricked into working in a brothel, but before losing her virginity there, escapes with a man named Charles with whom she has fallen in love. After several months of living together, Charles is sent out of the country unexpectedly by his father, and Fanny is forced to take up a succession of new lovers to survive.