London, 1888: on the night of the third Jack the Ripper killing, soft-spoken Mr. Slade, a research pathologist, takes lodgings with the Harleys, including a gloomy attic room for "experiments." Mrs. Harley finds Slade odd and increasingly suspects the worst; her niece Lily (star of a decidedly Parisian stage revue) finds him interesting and increasingly attractive. Is Lily in danger, or are her aunt's suspicions merely a red herring?