The narrator, Montresor, introduces the story by telling us that he was insulted by Fortunato, therefore he vows to get revenge on him. He puts this plan into action when he encounters Fortunato during the carnival season. Montresor tells Fortunato that he has acquired a pipe of what seems to be Amontillado, but he is not sure, so he wants Fortunato to take a look. Fortunato has had too much to drink, so he easily believes Montresor's lie.
As the two men are about to head towards Montresor's palazzo, Montresor notices that Fortunato may have a severe cold, so he acts concerned about Fortunato's health. He says that, rather than risking his health by taking him to the damp and nitre covered vaults, he will consult Luchresi. However, Fortunato insists on going: ""The cold is merely nothing. Amontillado! You have been imposed upon. And as for Luchresi, he cannot distinguish Sherry from Amontillado" (Poe, 22). Montresor easily gives in to Fortunato and they quickly make their way towards Montresor's palazzo.
Montresor takes Fortunato to the catacombs, and when Fortunato's health starts deteriorating, he offers him wine to supposedly help him recover. While walking through the catacombs, Fortunato asks about the Montresors' family arms, and Montresor answers, ""A huge human foot d'or, in a field azure; the foot crushes a serpent rampant whose fangs are imbedded in the heel"" (Poe, 47). He also asks about the Montresors' motto, to which Montresor replies, ""Nemo me impune lacessit"" (Poe, 49). As they continue through the catacombs, getting closer to the Amontillado, Montresor becomes more confident and gives Fortunato more wine in order to further dull his senses.
When they finally stop walking, Montresor tells Fortunato that he has kept the Amontillado inside the area in front of them. Excited to see the Amontillado, Fortunato enters the room, only to be obstructed by the rock wall encircling the small area. As he stands there, confused, Montresor jumps at the opportunity to launch a surprise attack and chain Fortunato to the rock wall. Fortunato, however, is still in shock from what happened, so all he does is ask Montresor about the Amontillado, not realizing the grave danger he is in.
After trapping Fortunato, Montresor starts to build a wall at the entrance of the small enclosure. As he is working on the wall, he hears a cry from inside the enclosure and realizes that Fortunato is no longer intoxicated. When Montresor finishes the seventh layer of the wall, he checks on Fortunato and is met with loud screams filled with fear. He is initially frightened by this, but quickly reassures himself and begins to scream back at Fortunato, which causes him to go silent once again.
Montresor builds the rest of the wall, leaving only a single stone to be fitted into the wall. This is when he hears Fortunato laugh before saying, ""Ha! ha! ha! — he! he! he! — a very good joke, indeed — an excellent jest. We will have many a rich laugh about it at the palazzo — he! he! he! — over our wine — he! he! he!"" (Poe, 79). Montresor continues to reassure Fortunato, but when he eventually stops responding, Montresor gets agitated and throws a torch into the enclosing. From inside, he hears nothing but the jingling of bells, which sickens him and causes him to hastily puts the last stone in its place.