crime. The opening of the novel sets the stage for a gripping mystery as it recounts the details of the attempted murder of Mlle Stangerson, who is found critically injured in her locked bedroom. Various characters, including her father and a servant, react in panic as they discover her plight and realize the impossibility of an assailant escaping from the sealed room. Rouletabille is introduced as the key figure who takes on the challenge of uncovering the truth behind the strange events, including tracking down clues like a revolver and questioning the credibility of witnesses. As the story unfolds, Leroux builds intrigue with hints of supernatural elements, making the reader eager to discover how the mystery will be resolved. (This is an automatically generated summary.)