Who is Helen Stoner in "The Adventure of the Speckled Band"?
Helen Stoner is the young woman who travels to London to seek out Holmes' help with a problem involving her stepfather. Helen and her sister Julia lived with their stepfather, Dr. Roylott, after the death of their mother. Dr. Roylott is a miserly, bad-tempered man whom Helen suspects was involved in the death of her sister some years earlier.
The plot of the story involves a small inheritance the girls' mother left for them should they marry. This would, of course, cut into the money left to Dr. Roylott, and he devises an elaborate scheme to prevent the daughters from marrying by ensuring their deaths. Before he can kill Helen, however, Holmes and Watson are called in and naturally solve the case!