Montresor is actually happy to bump into fortunate, A know-it- all man who is a gullible alcoholic with a successful job and family. "I was so pleased to see him" explains Montessori.
Montresor manipulates and lures Fortunato into his plan, and starts by getting him very drunk to make him weaker.
The two of them decide to explore some catacombs, with Montresor pretending to be worried for Fortunato's health due to his old allergy. With Funato getting weaker due to the mold and unhealthy condition in the catacombs and Montresor tries to take advantage of him.
Montresor finally takes advantage of Fortunato and chains him up between the catacombs, he did this with multiple stories down enough for no one to hear his cry
Montresor lisens to Fortunates cry for help, with an evil smirk, but does absolutely nothing