The arrival of Abbe Faujas in the provincial town of Plassans has profound consequences for the community, and for the family of François Mouret in particular. Faujas and his mother come to lodge with François, his wife Marthe, and their three children, and Marthe quickly falls under the influence of the priest. Ambitious and unscrupulous, Faujas gradually infiltrates into all quarters of the town, intent on political as well as religious conquest. Intrigue, slander, and insinuation tear the townsfolk apart, creating suspicion and distrust, and driving the Mourets to ever more extreme actions. 
The fourth novel in Zola’s Rougon-Macquart sequence, The Conquest of Plassans returns to the fictional Provençal town from which the family sprang in The Fortune of the Rougons. In one of the most psychological of his novels, Zola links small-town politics to the greater political and national dramas of the Second Empire.