What nudges someone so close to the edge, and then allows him or her to make the leap? In Edgar Allen Poe's "The Cask of Amontillado", one character crosses that invisible line. He commits the murder of one who wronged him. Montresor's motivations for the crime are fueled by his incredible intellect, his ruthlessness, and his need for vengeance. With all Montresor had inside, it took one even for him to make that final leap.
The perfect crime cannot be committed if the mind behind it is imperfect. Montresor relies not on his brute strength, but his intelligence to exact his revenge. Fortunato's weakness is easily exploited and Montresor uses this knowledge to manipulate him. When attempting to lure Fortunato into the catacombs, Montresor says, "AS you are engaged, I am on my way to Luchresi. If any one has a critical turn it is he" (220). While Fortunato responds, ""Luchresi cannot tell Amontillado from Sherry come let us go"(220). Montresor is showing little acceptance of Fortunato's ability in such a way that his victim insists on being led into the trap. Once inside the catacombs, Montresor reveals his "weapon" to Fortunato without any hesitation. With the mention of the masons, and their symbol, the trowel, Montresor answers by "producing from beneath the folds of my roquelaire a trowel"(222). Perhaps arrogance is displayed at that moment, Montresor knowing that Fortunato would never realize his true intentions, so in a way he subtly hints to him the fate that waits.
Montresor's residence itself has been prepared for the crime. He knew what had to be done for the servants to leave. Montresor says, "I had told them that should not return until the morning, and had given them explicit orders not to stir from the house. These orders were sufficient to insure their immediate disappearance as soon as my back was turned"(221). Montresor knows how people behave; he knows how to manipulate those around him to accomplish what he deems necessary.