This is the scene where Montresor meets Fortunato at the festival. He tells him about the Amontillado, noticing he is drunk and sick. He suggests that he shouldn't go, but Fortunato insists he will, saying "Let us go, nevertheless. The cold is merely nothing. Amontillado! "(Edgar Allan Poe, 22).
In this scene as they're walking down the cave, they have to stop because Fortunato has a bad cough. Montresor can see the film in his eyes, and knows he is very intoxicated. He asks if he wants to go back and he responds with, "the cough's a mere nothing; it will not kill me. I shall not die of a cough."
They've finally reached the Amontillado. Fortunato is too excited about the Amontillado to realize that there are human remains and bones everywhere and that this is s a trap.
As Fortunato is astounded by the Amontillado, Montresor is shackling him into the niche, for he will be forever stuck. Montresor tells him he must leave him here.
Montresor quickly realizes that his intoxication is wearing off, so he must close off the niche quickly. Fortunato notices what is happening and begs Montresor, "Let us be gone, for the love of God, Montresor!" (Edgar Allan Poe, 81-84). But it is too late, as the cave is blocked off. Montresor calls his name, but receives no response from Fortunato.
Montresor only hears the struggle of Fortunatos bells trying to escape the shackles, as he places the last couple of stones to completely block off the cave.