Examine the role of the narrator, the clues left for the reader, and the overall impact on the short story.

“The Vane Sisters” is a 1951 short story written by famed novelist Vladimir Nabokov. In it, a French literature professor remembers his encounters with two sisters, Sybil and Cynthia Vane, who have died and now he fears their ghosts may be haunting him. The plot is very simple and has a steady flow and Nabokov uses his characteristic language and style to make the story more interesting and structured.
“The Vane Sisters” is most famous in literature, especially in the short story genre, for having an “unreliable narrator.” There are only several things we know of the narrator of the story:
He teaches French Literature at a New England women’s college.
He describes himself as a very meticulous man that pays attention to every detail.
Cynthia Vane suspects her sister, Sybil Vane, is having an affair with D., a colleague of the narrator, and so she asks the narrator to help her end it.
Sybil Vane was a former student of his and she left her suicide note in a French essay she was assigned to write.
He tries and fails to save Sybil’s life and is left to console Cynthia. As a skeptic, he’s fairly amused by her obsession with the paranormal and often mocks her, and this is what brings their relationship to an end.
Later on, upon meeting his colleague, he learns that Cynthia has died as well and now believes that the ghosts of the Vane sisters are haunting him. He becomes very paranoid and is unable to sleep.
This tells us that the narrator is, in fact, not who he says he is. He doesn’t really pay attention to detail, he’s not very observant or conscious of his surroundings and proves to be very untrustworthy. By leaving numerous clues and hints throughout the story, Nabokov masterfully manages to deceive the readers into thinking that they have been following the plot all along. Using his typical plot twist at the end, he unveils that the narrator is actually quite unreliable.
The acrostic used in the final paragraph solidifies this point as well. Nabokov ends the story, writing:

"I could isolate, consciously, little. Everything seemed blurred, yellow-clouded, yielding nothing tangible. Her inept acrostics, maudlin evasions, theopathies--every recollection formed ripples of mysterious meaning. Everything seemed yellowly blurred, illusive, lost."

Using the acrostic composition, we can form two separate sentences with the first letters of each word: Icicles by Cynthia. Meter from me Sybil. With this we realize that the icicles and the shadows the narrator meticulously described at the beginning and used to proudly showcase his intelligence and ability to notice even the smallest of things, were, in fact, tricks that the Vane sister used to ridicule him.