Satan-worshiper Prince Prospero invites several dozen of the local nobility to his castle for protection against an oncoming plague, the Red Death. Prospero orders his guests to attend a masked ball and, amidst a general atmosphere of debauchery and depravity, notices the entry of a mysterious hooded stranger dressed all in red. Believing the figure to be his master, Satan, Prospero is horrified at the revelation of his true identity.