The story is told in first person, so we don’t explicitly learn the narrator’s name until near the end. Until then, we’ll call him “the narrator.” Here we go.
The narrator begins by telling us that Fortunato has hurt him. Even worse, Fortunato has insulted him. The narrator must get revenge. He meets Fortunato, who is all dressed up in jester clothes for a carnival celebration − and is already very drunk. The narrator mentions he’s found a barrel of a rare brandy called Amontillado. Fortunato expresses eager interest in verifying the wine’s authenticity.
So he and the narrator go to the underground graveyard, or “catacomb,” of the Montresor family. Apparently, that’s where the narrator keeps his wine. The narrator leads Fortunato deeper and deeper into the catacomb, getting him drunker and drunker along the way. Fortunato keeps coughing, and the narrator constantly suggests that Fortunato is too sick to be down among the damp crypts, and should go back. Fortunato just keeps talking about the Amontillado.
Eventually, Fortunato walks into a man-sized hole that’s part of the wall of a really nasty crypt. The narrator chains Fortunato to the wall, then begins to close Fortunato in the hole by filling in the opening with bricks. When he has one brick left, he psychologically tortures Fortunato until he begs for mercy – and we finally learn the narrator’s name: Fortunato calls him “Montresor.”
After Fortunato cries out Montresor’s name, he doesn’t have any more lines. But just before Montresor puts in the last brick, Fortunato jingles his bells. Then Montresor finishes the job and leaves him there to die. At the very end, Montresor tells us that the whole affair happened fifty years ago, and nobody has found out.