The narrator arrives at the House of Usher and realizes that it's very run down. There is a crack that runs from the roof to the ground. It was haunting from the outside. He is there to help his childhood friend, Usher, through hard times.
Once he gets in the house and sees Usher, the narrator realizes how pale and ill his old friend is. Usher tells the narrator that his nerves are heightened and that he is paranoid. The narrator spends several days with Usher in that house, passing the time trying to cheer his friend up. Meanwhile, Usher's sister Madeline is severely ill with an intriguing sickness.
Eventually, Madeline dies. Usher wants to bury her in the vaults, just to keep her in the house and away from scientists who might want to examine her since her disease was strange. The narrator helps Usher put his sister in the tomb when he notices that Usher and Madeline are twins.
Usher becomes very uneasy after burying his sister. One night, the narrator cannot sleep, and neither can Usher. The narrator decided to read "Mad Trist" by Sir Launcelot Canning to pass this horrible night. As he reads, he hears noises that correspond to what the story describes. Suddenly, everything becomes scary.
The narrator notices that Usher is muttering to himself. He says that he has been hearing things for days and that he believes they buried Madeline alive. He screams "We have put her living in the tomb!" Madeline emerges bloody and weak at the door. She attacks her brother, dying in the process. Usher dies of fear.
The narrator fled the house, scared. As he leaves, he sees a light. The house cracks along the crack that ran from the roof to the ground, and then it crumbles to the ground, leaving only fragments of the "House of Usher."