Isabella is an unmarried, wealthy woman in later middle age who lives in a lavishly decorated home. She maintains a rich external life filled with travel, collecting exotic furnishings and cultivating an extensive garden. To the observer in her drawing room, she presents a quiet indifference, keeping her inner thoughts and emotions completely concealed. She values her privacy, safely guarding her personal correspondence and memories from outside intrusion.

The unnamed narrator observes Isabella Tyson's home and garden from the depths of a sofa. Using the ambiguous pronoun "one," the narrator acts as a self-conscious presence who is deeply interested in Isabella's private life. Operating like a hidden naturalist watching shy animals, the narrator frequently invents elaborate details about the house's owner based solely on her possessions. The narrator holds strong opinions about the danger of hanging mirrors in homes.

The postman is a local worker who abruptly interrupts the stillness of the house by leaving letters on a marble table. His brief appearance brings the active outside world into the quiet drawing room. The marble-looking envelopes he leaves behind prompt further speculation about the private correspondence of the house's owner.