The only problem in “The Cask of Amontillado” is to lure Fortunato down into the catacombs where Montresor can leave him entombed. That is what the story is about. Being the last person seen with Fortunato would be Montresor’s biggest concern. Poe deliberately made this problem more complicated by deciding to dress the intended victim in such a way as to attract maximum notice.
He had on a tight-fitting parti-striped dress and his head was surmounted by the conical cap and bells.
Everybody would remember seeing Fortunato. He even has bells on his cap which jingle with every step. But by making this boisterous exhibitionist so conspicuous, Poe distracts all attention from his companion. Some revelers will remember that Fortunato had a companion, but no one will be able to identify him. Montresor is wearing a black cloak and a black mask. He is like a shadow of the other man.
This harlequin costume with the bells is a stroke of genius. Poe solves Montresor’s problem by magnifying it. Imagine trying to steer a drunken man through the crowded streets during the big carnival without being recognized by anyone! Montresor is virtually invisible just because Fortunato is so extremely visible.
After all, he is an important, well-known man. How could he be concealed? Even if he were wearing a different costume, one that concealed his body and face completely, some people would still recognize him as Fortunato. The important point is for Montresor not to be recognized as Montresor. He wants to commit his crime with “impunity.”
Fortunato chose the costume himself. He does not think of himself as a fool but as a jester. These court buffoons were noted for playing cruel jokes under the protection of noble patrons. No doubt many of the “thousand injuries” Montresor had suffered were in the form of sadistic jibes. It will give him added satisfaction to chain the jester to the wall in his appropriate costume.
Poe specifies that the motley is “tight-fitting.” This is to show that Fortunato is unarmed. Court jesters did not carry weapons. Montresor, on the other hand, has a rapier concealed under his roquelaire. If he can only get Fortunato down the stairs, then his victim’s fate is sealed. If he can’t entice him all the way to the narrow niche where two short chains are fastened to the rock wall, he might be forced to kill him with his rapier and drag him there.
Montresor’s bizarre antics when they are underground, including claiming to be a Mason and showing Fortunato his trowel, are meant to demonstrate Montresor’s vast relief. The hardest part of his problem is solved. Now there are just the two of them alone underground, and Fortunato will never be seen again.
There is only one conflict in "The Cask of Amontillado," and it is man against man. Montresor is the protagonist and Fortunato the antagonist. Montresor wants to lure Fortunato down into his catacombs and do exactly what he ends up doing to him. He has plenty of problems in accomplishing this. He also wants to make sure that nobody will ever suspect him of killing Fortunato. He plans far ahead. He pretends the strongest friendship for his intended victim and gets into the habit of referring to him as his friend and his good friend, so much so that he continues to do so while he is describing how he lured Fortunato to his terrible death. When Fortunato's disappearance is realized and investigated, no one will think of suspecting Montresor because he and Fortunato were such good friends.
Montresor invents a cask of Amontillado which he claims he bought at a bargain price but has doubts about its authenticity. He pretends that he was on his way to Luchesi since he was unable to find Fortunato that same night. The urgency suggests that he plans to buy more at the low price but has to assure himself it is genuine and has to act quickly before word gets around that a shipload of the gourmet wine is availalble. Fortunato probably would not have been so strongly motivated to go to Montresor's palazzo that very night if he wasn't afraid of having Luchesi find out about the Amontillado and possibly buy up the whole cargo. Fortunato naturally would like to buy some of the bargain-priced Amontillado himself--but he too has to sample it and make sure it is genuine. He is not motivated by the desire to help his friend. He is not motivated by a desire to show off his connoisseurship. He is not motivated by the desire to go all that distance just to drink a glass of groumet wine. He could buy Amontillado by the glass or by the bottle right in Venice if he wanted to. Amontillado isn't that rare. It is the bargain and the possibility of making a big profit that motivates him.
Fortunato is drunk, and Montresor keeps him drunk by giving him two bottles of French wine when they are in the catacombs. His conflict is not resolved until he has chained Fortunato against the wall and locked the padlock. There is no other important conflict in this story. There is no internal conflict. Montresor knows what he wants to do and has no serious misgivings about it. Looking for internal conflicts such as guilt or pity is a waste of time. He, of course, realizes that he can't change his mind after he has gotten Fortunato where he wants him.
"The Cask of Amontillado" is a tightly written story which leaves no room for any consideration of secondary external conlicts or primary internal conflicts. The problem of getting a drunken reveller dressed in a conspicuous costume, complete with a cap with ringing bells, down into the catacombs without being recognized by anybody on the crowded streets while keeping his victim drunk and compliant, while manipulating him by negative psychology, is sufficient. Anything more would be a distraction and would detract from the effect.