We can find the introduction to this story in the opening paragraph. It is here that Bowen reveals some key information to the reader concerning the setting of the story and information about its main character, Mrs. Drover.
For example, from this paragraph, we learn that Mrs. Drover is visiting her house in London, but she does not live there at the moment. In fact, she has another house in the country, and her London home is empty. Bowen uses imagery to emphasize the emptiness of the London house. For instance, Bowen describes how Mrs. Drover has to push open the door with her knee because of the "unwilling" lock. This use of imagery also creates an eerie, uncertain atmosphere.
In addition, we learn that it is late August, and the weather reflects this summery setting. The day is "steamy," for example, and the sun is "glittering."
Finally, another crucial aspect of the introduction is how Bowen builds suspense. By not telling the reader why Mrs. Drover's house is empty, the reader's interest is piqued. We want to know why this house is empty and, more importantly, what might be lurking inside.