How many stories does Vera tell, and how many people does she deceive in "The Open Window" by Saki?

In total, Vera deceives two characters: Mr. Frampton Nuttel, the skittish visitor, and Mrs. Sappleton, her aunt.

Learning that Mr. Nuttel is new in town and knows nothing of the Sappleton's, Vera concocts an elaborate story about a "great tragedy" that took place three years earlier. She tells Nuttel that her aunt keeps a large window open in hopes that her long-lost husband and brothers (presumably dead) will return from a tragic hunting trip.

The second tale she tells is to her aunt. Mr. Nuttel suffers a small breakdown when he sees the men returning from their hunting trip and dashes out the door. When asked by Mrs. Sappleton if she knew what was wrong with Mr. Nuttel, Vera explains that he is deathly afraid of dogs after once spending the night in a grave surrounded by ferocious canines. The men's spaniel probably spooked him.

Not only do the unfortunate Mr. Nuttel and Mrs. Sappleton fall prey to the Vera's joke but so do we as readers. The first story is so well-told that the reader is inclined to believe it. However, it is only after the second tale that we realize we are just as gullible as Nuttel.