"The Cask of Amontillado" is a short story by Edgar Allen Poe. The story only contains two main characters: Fortunato and Montresor. Initially you do not know that the narrator's name is Montresor because the story is told in first person.
At its root, "The Cask of Amontillado" is a revenge story. The reader is told that Fortunato has hurt the narrator. To make matters even worse, Fortunato has insulted Montresor. Gasp! That's totally a good reason for revenge by murder, right?
Montresor seeks out Fortunado at a party, where he finds Fortunato already drunk. So what does Montressor do? He tells Fortunato that he has a rare cask of Amontillado down in his cellar. Fortunato is very excited to see it and/or get a taste of it.
Montresor leads Fortunato deeper and deeper into his wine cellar/crypt all while getting Fortunato even more drunk. Upon reaching the end of the cellar, Montresor leads Fortunato into a little alcove/hole in the wall and chains him to the wall. Then Montresor starts to wall up the hole brick by brick. Fortunato begs and pleads for his life, but it all falls on deaf ears. Montresor finishes the block work and leaves Fortunato there to die. At the very end of the story, Montresor tells his readers that it has been 50 years and no one has found out yet.