Upon their arrival in Sussex, Mrs. Ferguson's maid announces that her mistress is ill, and Dr. Watson offers to help. He finds an agitated woman in the room upstairs – she speaks of all being destroyed, and of sacrificing herself rather than breaking her husband's heart. She also demands her child, who has been with the nurse, Mrs. Mason, ever since Mr. Ferguson found out about the bloodsucking incidents. Holmes examines the South American weapons displayed in the house and meets the children. While Mr. Ferguson is doting on his younger son, Watson notices that Holmes is gazing at the window. He cannot imagine why his friend is doing this.