The narrator tries to convince the reader that he is not mad and starts to tell the story.
The old man, who lives in the same house as the narrator, has a disgusting blue eye with a film on it. Even though the narrator likes the old man, he decides to kill him to get rid of the disturbing eye.
The narrator goes to the old mans room every night at 12 pm for seven days. Each night he uses a lantern to shine directly at the eye, but the man never opens his eyes, so the narrator can't kill him.
Next night, the old man hears the narrator and wakes up. The narrator uses the lamp to shine right at the narrators eye and kills him by pulling the bed on the man until his heart stops beating. Then he cuts the man into pieces and hides them under the floor.
Called by a neighbor of the old man, who heard a scream, the police arrives. But the narrator tries to hide his crime by saying it was him who screamed and the old man was out of town.
While he´s talking to the police officers, he's noticing a strange feeling in his eye and his view begins to get worse. One police officer asks him :"What is wrong with your eye?" As the narrator looks in the mirror, he looks into the disgusting eye of the old man.