The unnamed narrator of the story is a "dreadfully nervous" character who disputes the allegation that he might be crazy. He contends that his disposition arises from a heightening of the senses: "Above all was the sense of hearing acute" (74). The narrator provides care for a wealthy elderly man. For some inexplicable reason, the narrator becomes obsessed with the diseased eye of the old man. The narrator likens it to a vulture’s eye and is so haunted by the Evil Eye that he decides to murder the old man.

He meticulously plans the murder. After one week of preparation, the narrator charges into the old man’s bedroom after midnight and kills him using the heavy bed the victim had been sleeping in to either crush or suffocate him. Even after the murder, the victim’s heart continues beating for many minutes. The narrator carefully dismembers the body in a tub. He conceals all the pieces under the floor boards.

At four o’clock in the morning, three policemen arrive. A neighbor heard a scream and notified the police. They are here to investigate. The narrator maintains his composure and even entertains the police. After all, he has committed the perfect crime. Suddenly, he hears a repetitive noise like the ticking of a watch. At first soft, the sound grows louder and louder. No one else hears it. What is the cause of the noise--paranoia, his conscience, auditory hallucinations, a supernatural clue, or (most likely) the sound of his own pounding heart? The narrator can no longer tolerate the thumping and confesses to the murder: "I admit the deed!--tear up the planks!--here, here!--it is the beating of his hideous heart!" (78)