When the narrator arrives late on the eighth night, though, the old man wakes up and cries out. The narrator remains still, stalking the old man as he sits awake and frightened. The narrator understands how frightened the old man is, having also experienced the lonely terrors of the night. Soon, the narrator hears a dull pounding that he interprets as the old man’s terrified heartbeat. Worried that a neighbor might hear the loud thumping, he attacks and kills the old man. He then dismembers the body and hides the pieces below the floorboards in the bedroom. He is careful not to leave even a drop of blood on the floor. As he finishes his job, a clock strikes the hour of four. At the same time, the narrator hears a knock at the street door. The police have arrived, having been called by a neighbor who heard the old man shriek. The narrator is careful to be chatty and to appear normal. He leads the officers all over the house without acting suspiciously. At the height of his bravado, he even brings them into the old man’s bedroom to sit down and talk at the scene of the crime. The policemen do not suspect a thing. The narrator is comfortable until he starts to hear a low thumping sound. He recognizes the low sound as the heart of the old man, pounding away beneath the floorboards. He panics, believing that the policemen must also hear the sound and know his guilt. Driven mad by the idea that they are mocking his agony with their pleasant chatter, he confesses to the crime and shrieks at the men to rip up the floorboards.

The narrator finds the inside of the house just as spooky as the outside. He makes his way through the long passages to the room where Roderick is waiting. He notes that Roderick is paler and less energetic than he once was. Roderick tells the narrator that he suffers from nerves and fear and that his senses are heightened. The narrator also notes that Roderick seems afraid of his own house. Roderick’s sister, Madeline, has taken ill with a mysterious sickness—perhaps catalepsy, the loss of control of one’s limbs—that the doctors cannot reverse. The narrator spends several days trying to cheer up Roderick. He listens to Roderick play the guitar and make up words for his songs, and he reads him stories, but he cannot lift Roderick’s spirit. Soon, Roderick posits his theory that the house itself is unhealthy, just as the narrator supposes at the beginning of the story.

Madeline soon dies, and Roderick decides to bury her temporarily in the tombs below the house. He wants to keep her in the house because he fears that the doctors might dig up her body for scientific examination, since her disease was so strange to them. The narrator helps Roderick put the body in the tomb, and he notes that Madeline has rosy cheeks, as some do after death. The narrator also realizes suddenly that Roderick and Madeline were twins. Over the next few days, Roderick becomes even more uneasy. One night, the narrator cannot sleep either. Roderick knocks on his door, apparently hysterical. He leads the narrator to the window, from which they see a bright-looking gas surrounding the house. The narrator tells Roderick that the gas is a natural phenomenon, not altogether uncommon.

The narrator decides to read to Roderick in order to pass the night away. He reads “Mad Trist” by Sir Launcelot Canning, a medieval romance. As he reads, he hears noises that correspond to the descriptions in the story. At first, he ignores these sounds as the vagaries of his imagination. Soon, however, they become more distinct and he can no longer ignore them. He also notices that Roderick has slumped over in his chair and is muttering to himself. The narrator approaches Roderick and listens to what he is saying. Roderick reveals that he has been hearing these sounds for days, and believes that they have buried Madeline alive and that she is trying to escape. He yells that she is standing behind the door. The wind blows open the door and confirms Roderick’s fears: Madeline stands in white robes bloodied from her struggle. She attacks Roderick as the life drains from her, and he dies of fear. The narrator flees the house. As he escapes, the entire house cracks along the break in the frame and crumbles to the ground.