The first thing the narrator tells us is that he doesn't "expect" us to believe the story he's about to write, or ask us to believe it (1).
He says he'd have to be crazy to think we'll believe him – he can hardly believe it himself.
Then he says he isn't crazy and isn't dreaming.
He is going to die the very next day, and has confess everything to set his story straight.
His purpose in writing the story is to give "the world" a the plain facts of "a series of mere household event" – read "stuff that happened around the house" (1).
The consequences of the things that have happened around this mans house have caused him intense fear, extreme discomfort, and have actually "destroyed" him (1).
But, he isn't going to go into the details of that.
Rather, he is going to present the facts, and hope that some reader can see that everything that happened, every thing that the narrator makes such a big deal about, is really "nothing more than an ordinary succession of very natural causes and effects" (1).
Even as a kid, the narrator was thought to have an attitude of "docility and humanity" (2).
His friends even made fun of him because he was too nice.
He loved animals, and his parents let him keep lots of pets, and he spent lots of time taking care of them.
The narrator's animal love stayed with him even as he grew from a boy, to a man, and he felt a particularly deep connection with his "faithful and sagacious dog" (2).
(Sagacious is another word for "clever" or "perceptive.")
While still a young man the narrator got married. He tells us that he and his wife didn't get along badly.
She noticed how much he loved animals and bought him lots of them, including – "a cat" (3).
This was a big cat – black, and gorgeous, and "sagacious" (4).
In fact, the cat was so smart and sensitive that the woman suggested, that, like the myth, the cat might be a witch, "in disguise" as a cat" (4).
Of course, the woman was just kidding around. The narrator only mentions this part because it's part of the story he's remembering.
So, the cat's name is Pluto, and the man loved him.
Pluto had to be kept from following the man out of the house.
This lovely relationship between man and cat continued for a few years.
But then – the man started drinking and suffered a personality change "for the worse," and of which he is much ashamed (6).
(The narrator doesn't say he started drinking – he says that his personality changed as a result of "the Fiend Intemperance." "Intemperance" means any excessive behavior or habits. In Poe's time, most often, excessive drinking.)
As the narrator drank more and more, he became a nastier character with each passing day.
He used "intemperate language" to his wife, and threatened to physically abuse her.
The pets were neglected and abused whenever the narrator was near them – except for Pluto the cat.
The "disease" of "Alcohol" got worse and worse (6).
Soon, even Pluto was made to feel the wrath.
The narrator came home one night, drunk, after partying in town.
He thought Pluto was trying to hide from him.
Furious, he grabbed Pluto, and Pluto bit him a little.
The narrator then turned into a complete angry demon.
Next, he takes out his "pen-knife" (a knife originally used for sharpening quill pens) (7).
Then he cuts one of the cat's eyes out with it.
The narrator feels extreme shame and horror to "pen" (or write) what he did to Pluto (7).
In the morning, when the narrator was sober again a little bad about what happened, but it wasn't that deep. He went right back to his drinking ways.
The cat (you'll be glad to know) got better.
Sure, his empty socket was nasty looking, but he didn't seem to be in "pain" (9).
For a while the man's feelings were hurt because Pluto didn't love him any more, but then Pluto started getting on his nerves.
The narrator was overcome with "the spirit of PERVERSENESS" (9).
Perverseness, the narrator says, is a natural part of human nature.
All people sometimes do things just because they know they aren't supposed to.
According to the narrator, human beings have a natural desire to break the law.