Before telling his tale, the narrator asserts that the Opera Ghost is not a phantom in the traditional sense but was rather a real—though mysterious—man. The narrator, an investigator, seeks to solve the tragic cases that occurred at the Paris Opera House 30 years ago. He believes the Opera Ghost may be behind the unexplainable events. The narrator speaks to many witnesses and concludes that the fanciful stories of the ghost have logical explanations. He thanks those at the Opera who told their stories and the families of the victims who urged him to share his findings.

La Sorelli, principal ballerina of the Paris Opera, prepares a speech for the departing managers M. Debienne and M. Poligny. A gaggle of young dancers invade her dressing room, crying that Jammes saw the Opera Ghost. Prior to this sighting, many dancers and stagehands claimed to have seen the ghost lurking about, and most people attribute any misfortune to the ghost's workings. Joseph Buquet, the chief sceneshifter, saw the corpse-like specter going into the Opera cellars. Gabriel, the chorus master, saw the ghost in his office and was injured while fleeing his room in fear.

The dancers worry the Ghost is listening to them, but when Sorelli opens the door, they see only an empty hallway.