"The Raven" deals with a lonely narrator who is pondering upon the loss of his loved one when he is suddenly visited by a talking raven. The raven, however, has a one-word vocabulary and anything the narrator asks it, the raven responds, "Nevermore."
The more detailed the narrator becomes in his inquiries of the raven, the more he realizes that he will never be reunited with his lost love Lenor in heaven after his death. He also comes to believe that the raven is an evil prophet come to torment him with this horrid realization for the rest of his days, as symbolized by the stubborn resistance of the raven to disappear back into the night.
"The Raven" is one of Poe's most famous and read poems partly because of the ingenious manner in which the plot develops. At first, the narrator is amused by the raven and imagines that it was probably owned previously by some unfortunate man whose bad luck caused him to utter the word "nevermore." The narrator also predicts that the raven is sure to leave him by morning, abandoning him like everyone else has. It is only when the raven responds to this with "nevermore" that the narrator begins to make the more frightening discoveries about the raven's visit.