The story ends when the police find the dead body of the man's wife, with the cat on her head. On the one hand it's outrageous, and even funny. At the same time, when we think about just how close these details can come to our own reality, it's sad and frightening. There is always some bizarre tragedy in the news. In Poe's day, too, sensational stories were all the rage. Such stories, like this one, can cause a broad range of emotions.
Like the news items we hear and read, "The Black Cat" doesn't end neatly, with all the questions answered. For example, we know the narrator is writing his confession the day before he's scheduled to be executed for the murder of his wife. But, we don't know if the sentence is carried out, or if the confession the man writes in his "felon's cell" does "unburthen [his] soul" (20). (By the way, "unburthen" means the same thing as "unburden.")
In the final lines of the story, the narrator describes the cat as "the hideous beast whose craft seduced me into murder, and whose informing voice has consigned me to the hangman" (32). The man confesses to some awful things, and even thinks some of them are wrong and bad, but ultimately, he blames the cat for everything.
We might expect a man confessing to express remorse and ask for forgiveness from a higher power. In this case the man is simply telling his story as he sees it. He does express remorse for his treatment of his wife and the cat, but here at the end, as we said, he blames the cat. He is "unbearthening" his soul by admitting that he blames the cat. He feels "almost ashamed" to admit his beliefs about the cat, and just how afraid he was of the animal (20). (It's important to note that he never feels completely ashamed of anything.)
The narrator seems to see the cat as having some master plan, which involves tricking him into murdering his wife, and then allowing himself to be walled up, so that he could blow the whistle on the narrator. In the world of Poe, this is a completely believable scenario.
This scenario does have a couple of potential flaws though. First of all, why would the cat want the man to kill his wife? Second, if the cat allowed himself to be walled up with the corpse, on purpose, why didn't he meow (or let his presence somehow be known) before the man banged on the wall?
Here's one possible answer to the first question: if the cat wanted the narrator to pay for murdering him, he would have to get the man to kill a person. Only if the narrator was caught murdering a person would the law intervene. Still, there isn't much in the narrator's account of the cellar scene to suggest that the cat intended for the man to kill his wife.
In answer to the second question, the cat probably passed out from lack of air and didn't even realize the chance had come until the man's knock brought him back to consciousness.
You might also be wondering how the cat, if he isn't a supernatural creature, survived for four days in the wall. Well, assuming he was somehow getting air, the last paragraph suggests that the cat was probably eating the dead body to survive.
The narrator tells us that when discovered, the woman's body was "clotted with gore" and describes the cat as having a "red extended mouth" (32). We were told that the narrator "buried the axe in her brain." As such, her brains and blood probably got on her body, and "clotted" or dried there. But, this is one of Poe's gorier stories, so we have to take things to their goriest conclusions. The clue is the cat's "red extended mouth." The cat's mouth isn't described as red anywhere else in the story. Here it is quite probably meant to remind us of blood.
Another issue to consider is what happens to the cat after the man is arrested. The memory of the cat certainly haunts the narrator. Otherwise, he wouldn't be writing about his experience with the creature. But, there is no mention of the cat's future after the story. Either the narrator doesn't have access to this information, or doesn't think it's important to the story. We hope the cat found a happy home.
Some readers think the ending shows justice at work, because the man is stopped from doing more damage, and is held accountable for his crimes. Others don't see any justice in the ending, because the man doesn't learn to value the lives of others, and continues to "blame the victim" for his crimes. What do you think?