Here's a summary:
The story is told from the perspective of an unnamed narrator who claims he is not mad, but insists on telling the reader about his murder of an old man. Driven by the old man's "vulture eye", which he finds repulsive, the narrator meticulously plans the murder over several nights, sneaking into the old man's room and watching him sleep.
On the eighth night, the narrator suffocates the old man, dismembers the body, and hides it under the floorboards. He believes he has committed the perfect crime. However, the narrator becomes increasingly paranoid and hears a pounding sound, which he believes is the old man's heart beating beneath the floorboards. This sound drives him to confess to the police who arrive to investigate the old man's disappearance.
The story explores themes of guilt, paranoia, and the unreliable narrator. The narrator's descent into madness is chillingly portrayed through his detailed account of the murder and his escalating paranoia. The story's ending, where the narrator's delusion takes over, leaves a lasting impression of the psychological torment of guilt and the fragility of the human mind.