The skillful narrator of "romance at short notice," Mrs. Stappleton's niece Vera, upon her perception of Framton Nuttel's nervous condition and lack of acquaintance with the area and its populace, fabricates a credible tale of how her uncle and her two counsins went hunting by departing through the window that is open upon them as they await Mrs. Stappleton. Incorporating details of truth into this tale, she lures Mr. Nuttel into believing the veracity of the men's having never returned. Mrs. Stappleton, Vera tells him, yet believes in her debilitated state of mind that they will come back.
So, when Mrs. Stappleton finally arrives in the sitting room, Nuttel patronizes her. When she exclaims, "Here they are at last!" he looks to the niece sympathetically; however, as he sees the girl staring out the window in horror, Framton Nuttel quickly looks himself. As the men approach, chatting with one another, Framton flies out the door and races away in reaction to Vera's look and the conclusion to her tall tale.
In the meanwhile, Mrs. Stappleton is baffled by Framton's reactions because she has no knowledge of what Vera has fabricated:
"A most extraordinary man, a Mr. Nuttel," said Mrs. Sappleton...." one would think he had seen a ghost."
Both Framton Nuttel and Mrs. Stappleton of Saki's "The Open Window" have reacted to the "romance at short notice" of Vera, Mrs. Stappleton's niece.
The reader's first reaction to Vera is in keeping with the description the narrator gives of her. She is a confident young lady, a "very self-possessed young lady." She is also fifteen. In our day, at fifteen, she may be viewed as young, silly, unaccomplished. But in Saki's day, a well bred young lady of fifteen living in a landed gentry's home may have had many accomplishments and, in another year, might be ready to become a governess or be married.
The reader is meant to have a positive reaction toward Vera at first so that the horror of her manipulation of Framton Nuttel and the resultant surprise ending--with accompanying manipulation of Mrs. Sappleton as well--will have the greatest impact. As the story progresses, we begin to react with a bit of suspicion as Vera tells her tale because of the narrator's ironic witticisms, such as is evident in the narratorial comment: "asked the niece, when she judged that they had had sufficient silent communion."
The reader's reaction to Nuttel (the slightly nutty protagonist) is fairly consistent throughout, although the reader feels increasing sympathy toward the end. The horror builds around him and becomes more intense, and he becomes increasingly distressed, as when he tries to change the topic:
To Framton it was all purely horrible. He made a desperate but only partially successful effort to turn the talk on to a less ghastly topic,....
The reader is meant to maintain a sympathetic reaction to Nuttel throughout so that, when the surprise hits, we feel the horror right along with him--and so that we feel mild outrage when Vera's true self is revealed: "Romance at short notice was her speciality."