How would you describe the mood in "The Cask of Amontillado"?

Your question was somewhat confused, so I have edited it
to focus on the mood in general in this excellent short story. The mood in this story is
one that is sinister, threatening and disturbing as we move ever further down into the
catacombs of Montresor's family home and we move ever closer to the grim revenge that he
has planned against Fortunato. It is important to focus on how the description of the
setting is used to create and sustain this mood. Consider the following
quote:

We
continued our route in search of the amontillado. We passed through a range of low
arches, descended, passed on, and, descending again, arrived at a deep crypt in which
the foulness of the air causes our flambeaux rather to glow than
flame.

Note the repetition of
the word "descended" - we are walking ever further deeper into the dark catacombs, so
much so that we are disorientated and we have no idea of where we are. What is clear is
that we have arrived at a crypt, where dead people are buried, and that the air is so
foul that even the torches are subdued. Clearly Poe is trying to set the scene for the
shocking events that are about to unfold.

I think another
key passage that helps create the mood of horror is when Montresor finally shackles
Fortunato into the alcove from which he will never
leave:

In an
instant he had reached the extremity of the niche, and finding his progress arrested by
the rock, stood stupidly bewildered. A moment more and I had fettered him to the
granite. In its surface were two iron staples, distant from each other about two feet
horizontally. From one of these depended a short chain, from the other a padlock.
Throwing the links about his waist, it was but the work of a few seconds to secure it.
He was too much astounded to
resist.

What strikes me about
this passage is the way that Montresor is able to describe the chains and their location
with cool, calm, precision, even while he is planning a most heinous crime and a
terrible death. The tone he takes adds to the mood of horror that dominates this
excellent but terrifying work of short fiction which lingers in the readers' minds long
after it has been finished.