Saki's "The Open Window" follows the normal order of exposition, complication with rising action, climax, falling action, and denouement.
In the exposition, major characters are introduced. These characters are the protagonist, Framton Nuttel, who arrives at the country home of the Sappletons'. They are acquaintances of Nuttel's sister. He is there with letters of introduction from his sister, in the hope that his stay in the country will help his nervous condition. Since Mrs. Sappleton is not ready to receive her guest, she sends her niece Vera, the antagonist, to visit with him until she comes down to the parlor. Vera is a "very self-possessed young lady of fifteen."
In the complication, or inciting incident of the plot, Nuttel reveals to Vera that he has "a nervous condition" that his sister believes can be alleviated by Nuttel's resting in the country. Hearing this, Vera asks Nuttel if he knows anyone in the area; when he replies that he knows no one, the clever and creative Vera creates her tale of "the great tragedy."
During the rising action, Vera weaves her tale about Mrs. Sappleton's husband and her two young brothers who went out to hunt but never returned. Unfortunately, when they crossed the moor on their way to their favorite snipe-shooting ground, they were all "engulfed in a treacherous piece of bog." Vera tells Framton Nuttel that no bodies were recovered: "Poor aunt always thinks that they will come back someday. That is why the window is kept open...I almost get a creepy feeling that they will walk in through that window." Then, Mrs. Sappleton finally comes into the room. Just as Vera has told Nuttel, her aunt anticipates the return of her husband and her brothers. She apologizes for the open window, explaining that her husband and brothers will be home soon, and she likes for them come in through the window so that they and their wet things stay off the carpets.
In the climax, Mrs. Sappleton has "rattled on cheerfully about the shooting and the scarcity of birds." She has also listened to the ailments of Framton Nuttel. But, "suddenly [she] brightened into alert attention." "Here they are at last!" she exclaims. Vera stares out the window "with dazed horror in her eyes." Framton swings around in "a chill shock of nameless fear" and looks in the same direction as the others. In the twilight, there are three figures walking toward the open window. "Here we are, my dear," says the man. "...fairly muddy, but most of it's dry. Who was that who bolted out as we came up?" [Framton has run out of the room.]
During the Falling Action, Framton Nuttel has fled in terror after running out of the room, because Vera's tall tale has become real for him. The naive Mrs. Sappleton observes that he is a "most extraordinary man....One would think he had seen a ghost." The devious Vera calmly suggests that Nuttel has a fear of the dogs.
With the Denouement, the question of why Framton Nuttel has run off is supposedly explained by Vera. She fabricates her last story about Nuttel's once having been hunted by "a pack of pariah dogs" on the banks of the Ganges River in India as the cause of his fear. Indeed, "[R]omance at short notice was her specialty." No one is the wiser about Vera.