In the kingdom of Prince Prospero, a disease, the Red Death, viciously and gruesomely kills all who contract it. As it runs its course throughout his kingdom, Prospero decides to escape its grasp by inviting all the nobles to his castle and welding the doors shut, so they can all wait out the plague in his lavishly decorated castle.
One night, Prospero holds a masquerade ball. He decorates seven rooms, each with a different color: blue, purple, green, orange, white, violet, and black. All the rooms are magnificently ostentatious with stained glass windows of the coordinating color, except for the final black room which has red stained glass windows. This room is so disturbing that no one enters the room. Even more mysterious is a large ebony clock which chimes every hour, halting the exaltation of revelers with its foreboding strike.
As the party goes on and the clock is about to strike midnight, an enigmatic guest appears dressed as a plague victim. Deeply disturbed by a guest's poor judgment, Prospero engages with the visitor, finally pursuing him with a dagger through the seven colored rooms. As he reaches the figure in the final room, Prospero falls dead. The other guests subdue the intruder and forcibly remove his mask, finding, to their horror, there is no one beneath the costume. They also die. The Red Death infiltrated the castle, despite Prospero’s efforts to escape it.