what is the exposition of the story?

This very descriptive and atmospheric story is in large
part all about setting and how it can function almost like a character. The vivid
descriptions of the castle's chambers, each one a different color and full of
furnishings of the same hue, create a powerful picture in the reader's eye and help
establish the heightened mood of the celebration at the heart of the action. Color is
important to the story because it refers to the disease/plague that affects the
characters, and refers to the central event in the title. The masque is a celebratory
event but is also the catalyst for character epiphanies. When the corruption of the
prince and his guests is revealed, it becomes clear that the plague may be a form of
punishment that is waiting to claim the lives of those who behave cruelly or selfishly
towards others. The decadent descriptions of the castle underscore the shallow values of
this culture, and Poe may in fact be suggesting that the plague is a result of human
corruption.