At the beginning of the story the narrator tells us he is not mad but just nervous and diseased but can tell us the story calmly (internal conflict). All the narrator wanted to do was murder the old man because of his "vulture" eye.
The narrator wants to prove his sanity to the readers. The narrator is nice to the old man for a week straight. Every night at midnight the narrator would look in on him and watch him sleep. He would open the lantern each night to see if the old man's eye was open. then later that day the narrator would ask the old man how he slept.
The dead hour of the eighth night (foreshadowing). They both didn't move a muscle as if the old man fears death stalking upon him (personification). The narrator opens the lantern and sees the eye is open. The narrator hears a low and dull sound the narrator thinks it's the old man's heart. As he thinks the heart beat is getting louder and louder. The narrator is scared a noise will be heard by a neighbor.
The narrator jumped into the room with a loud yell. He then smothered the old man with the mattress.
The narrator dismembers the body in the bath tub. He hides the body under the floor boards. The police arrived because the neighbor heard a shriek. The police search and the Narrator invites them in to sit in the room. The narrator sits on the floor board where he hid the body.
The narrator confesses to the murder because he cant stand the sound of the heart beat, symbolizing his own heart beat. He acts crazy and each second he does, the low and dull sound gets louder.