The narrator wrote Usher a letter to come and see him for a short amount of time. When Usher arrives to the house he notices how pale and sickly looking the house is.
When Usher finally sees the narrator he sees how the state of the house is very much like the state of the narrator. The narrator appears to be coinciding with the state of the house.
The narrator then begins to tell Usher about how his twin sister was dying. He then decides to keep her body in the wall until he makes plans to bury her.
During the middle of the night Usher began to hear strange noises that started to freak him out. He heard them from the basement and so he decided to go figure out what it was.
Usher continued to walk closer and closer to where the twin sister was and he began to hear screams louder and louder and Madeline slung open the door and began to walk near Usher and collapsed and died.
As the narrator continues to watch the house begins to disappear more and more until the house is completely gone.