Before beginning his account, the unnamed narrator claims that he is nervous and oversensitive but not mad, and offers his calmness in the narration as proof of his sanity. He then explains how although he loved a certain old man who had never done him wrong and desired none of his money, the narrator could not stand the sight of the old man's pale, filmy blue eye. The narrator claims that he was so afraid of the eye, which reminds him of a vulture's, that he decided to kill the man so he would no longer have to see it.
Although the narrator is aware that this rationalization seems to indicate his insanity, he explains that he cannot be mad because instead of being foolish about his desires, he went about murdering the old man with "caution" and "foresight." In the week before the murder, the narrator is very kind to the old man, and every night around midnight, he sneaks into the old man's room and cautiously shines a lantern onto the man's eye. However, because the eye is always closed and the narrator wishes to rid himself of the eye rather than the man, the narrator never tries to kill him, and the next morning, he again enters the chamber and cheerfully asks how the old man has slept, in order to avoid suspicion.
On the eighth night, the narrator is particularly careful while opening the door, but this time, his thumb slips on the lantern's fastening, waking the old man. The narrator freezes, but even after an hour, the old man does not return to sleep because he feels afraid and senses someone's presence. At length, the narrator decides to slowly open the lantern until the light shines on the old man's eye, which is wide open. The narrator's nerves are wracked by the sight, and he fancies that because of his oversensitivity, he has begun to hear the beating of the old man's heart.