A disease known as the Red Death plagues the fictional country where this tale is set, and it causes its victims to die quickly and gruesomely. Even though this disease is spreading rampantly, the prince, Prospero, feels happy and hopeful.
He decides to lock the gates of his palace in order to fend off the plague, ignoring the illness ravaging the land. After several months, he throws a fancy masquerade ball.
For this celebration, he decorates the rooms of his house in single colors.
The easternmost room is decorated in blue, with blue stained-glass windows. The next room is purple with the same stained-glass window pattern.
The rooms continue westward, according to this design, in the following color arrangement: green, orange, white, and violet. The seventh room is black, with red windows.
Also in this room stands an ebony clock. When the clock rings each hour, its sound is so loud and distracting that everyone stops talking and the orchestra stops playing.
When the clock is not sounding, though, the rooms are so beautiful and strange that they seem to be filled with dreams, swirling among the revelers.
Most guests, however, avoid the final, black-and-red room because it contains both the clock and an ominous ambience.
At midnight, a new guest appears, dressed more ghoulishly than his counterparts.
His mask looks like the face of a corpse, his garments resemble a funeral shroud, and his face reveals spots of blood suggesting that he is a victim of the Red Death.
Prospero becomes angry that someone with so little humor and levity would join his party. The other guests, however, are so afraid of this masked man that they fail to prevent him from walking through each room.
Prospero finally catches up to the new guest in the black-and-red room. As soon as he confronts the figure, Prospero dies. When other party-goers enter the room to attack the cloaked man, they find that there is nobody beneath the costume.
Everyone then dies, for the Red Death has infiltrated the castle.
“Darkness and Decay and the Red Death” have at last triumphed.