How does Prince Prospero plane to escape the "Red Death" in the story, The Masque of the Red Death?

In order to escape the spread of the plague, Prince Prospero invites "a thousand hale and lighthearted friends from among the knights and dames of his court" to seal themselves "in deep seclusion" in an abbey of his castle, allowing no one to enter or leave. With adequate provisions, Prospero and his privileged guests attempt to "bid defiance to contagion," by sealing themselves off from the suffering and disease spreading throughout the rest of their country.