"So you see he would have been a very profound old man, indeed, to suspect that every night, just at twelve I looked in upon him while he slept."
The narrator watches the old man sleep for 7 nights. This is the last night the narrator watches the old man.
The old man wakes up from his sleep. The narrator is not moving and continues to watch the old man. (Silhouette of the narrator is in the bottom left).
The narrator jumps into the old man's house because he saw the old man's eye. The narrator is going to jump on the old man and kill him. The old man lets out a shriek as the narrator was about to jump on him.
"Villians! Dissemble no more! I admit the deed!-tear up the planks!-here, here! it is the beating of his hideous heart!"
After the narrator kills the old man, the narrator disposes of the body before anyone can find out.
The neighbor of the old man heard the old man's shriek so the neighbor called the police. The police arrived and the narrator is acting calm and collected, but he keeps hearing the old man's "heartbeat" in his head and it is getting on his nerves.
The narrator finally snaps because he can't take the beating sound of the old man's heart anymore, so he confesses to the police.