The opening of the story introduces the de Verseuil family as they settle into a gothic castle in Normandy, believed to be haunted. One evening, after hearing mysterious screams from their children, Monsieur and Madame de Verseuil are alarmed and rush to investigate. They find their children terrified, claiming they were attacked by a ghost. As they recount their terrifying experiences, it becomes clear that their fears stem from ignorance and superstition. The arrival of the village priest offers a rational perspective, as he explains that the supposed spirit is nothing more than a simple bat. This sets the stage for the overarching theme of the book: the importance of reason and courage to confront irrational fears. (This is an automatically generated summary.)