The main conflict in "The Open Window" develops with the blurring of lines between the imagination and reality by Vera for whom "[R]omance at short notice was her specialty."
When the nervous and fidgety Framton Nuttel tries to utter the correct words to Mrs. Stapleton's niece, who has been sent to occupy him while she finishes her toilette, the precocious Vera realizes his discomfiture and sets about to take advantage of his nervous condition by fabricating a tall tale about her male relatives, framing it with the true occasion of his two brothers-in-law and Mr. Stappleton's going out the French doors/window on a hunt. Knowing that the men will return from their hunt by entering through this window, Vera tells Framton that they had been "engulfed in a treacherous bog," and their bodies were never found. But, her poor aunt believes they will return, along with the spaniel who accompanied them. Embellishing her mischievous tale further, Vera says as she exhibits a shudder,
"Do you know that on still, quiet evenings like this, I almost get a creepy feeling that they will walk in through that window--"
At this point Mrs. Stappleton enters. Somewhat unnerved by Vera's ghost story, Framton Nuttel tells the lady that his doctors have recommended that he have complete rest without excitement. But, at this point, the men return from the hunt, and Mrs. Stappleton cries out, "Here they are at last! Just in time for tea...." After hearing Vera's tale, Framton turns to her with sympathy for Mrs. Stappleton, but sees that Vera looks horrified. Her pretense leaves him in "nameless fear" as he views the men entering through this window, and he rushes outside and down the road. Truth mixed with fiction has terrified Framton Nuttel.