Madame Husson, the model of virtue in Gisors, is promoting chastity in her town by seeking to crown a rosière (i.e. Rose Queen, a girl of unimpeachable virtue). However, no girl can stand up to the investigations that take place, and Madame Husson crowns the village idiot, Isidore, as the 'rosier' (Rose King). He uses his reward to "slum it" in Paris.