The exposition of "The Masque of the Red Death," of course, introduces the setting, the characters, and the basic situation as well as providing some background information: a plague, called "the red death" has "long devastated the country." It is hideous, fatal, and causes those around it much horror and fear of contracting it. However, the wealthy Prince Prospero, with his allegorical name, fears it not. For, he feels that his prosperity will provide a fortress against this death of pain and red stains. Summoning together a thousnad "light-hearted friends from among the knights and dames of his court," they sequester themselves in the seculsion of one of his castellated abbeys, which were often used as fortresses.
Together with ample provisions, they decide to fortify themselves against this plague; they resolve to not despair or become hysterical so that they will neither open nor close any entry through which the red death can enter the abbey. Poe writes,
All these and security were within. Without was the "Red Death."
This sentence sets up the complication of the narrative with its suspense, and from this point the rising action takes place.