What happens in Edgar Allan Poe’s “The Cask of Amontillado”?

In Edgar Allan Poe’s short story "The Cask of Amontillado," the narrator, an aristocrat named Montresor, seeks revenge against an acquaintance named Fortunato for a series of perceived insults.

During a carnival, Montresor encounters a drunken Fortunato and lures him to his palazzo under the guise of seeking an expert opinion on a cask of amontillado. Montresor leads him deep into the family catacombs, navigating past skeletons and through the damp, dark vaults. Once they reach the deepest part of the crypt, Montresor chains the unsuspecting Fortunato to a wall and proceeds to entomb him alive by bricking up the entrance to the small chamber. The story is a chilling exploration of cold-blooded vengeance and irony.1