Plot Summary:As she fears for her life, Helen Stoner seeks Sherlock Holmes' assistance. She lives with her step-father Dr. Grimesby Roylott, a difficult man who is prone to bouts of temper. She tells Homes that some years previously, her older sister Julia had died in unexpected circumstances. She had asked Helen if she ever heard the sound of a whistle at night. Helen admitted that she had not. Just a few weeks before she was to marry, Julia came tumbling out of her room, screaming; she died within minutes. Now Helen, who is also soon to be married, finds that her step-father has moved her into her late sister's room. During her first night there, she hears the whistle that her sister had asked about.
A young woman asks for Holmes' help when her ill-tempered stepfather moves her into the same room where her sister died under mysterious circumstances.