After several successful months avoiding contamination, Prospero throws a lavish masquerade ball to celebrate their fortitude and resilience. For this celebration, he decorates seven rooms in his eccentric estate in monochrome colors. The easternmost room is decorated with ornaments and tapestries entirely in blue, complete with blue stained-glass Gothic windows. The next room is purple with purple stained-glass windows. The rooms continue westward, according to this design, in the following color arrangement: green, orange, white, and violet. The use of the stained glass is particularly effective because, as the only light source, they bathe each room in colored light and fantastical shadows that match the hues of each room. The narrator informs the reader that Prospero’s estate is unlike a typical palace in which the suites form a straight line that, with the help of sliding doors, can all be seen at once. Instead, Prospero’s love of the bizarre has resulted in an estate in which you can only see one room at a time due to the elaborate architectural twists and turns. 

The seventh room, however, is distinct from the other six rooms in terms of design and effect. The room’s velvet ornamentation and furnishings are all black. However, unlike the other rooms in which the color of the Gothic stained-glass windows match the color of the room, the stained-glass windows in the black room are red. Specifically, the panes of glass are described as being a deep blood-red color. The deep red lighting creates an unnerving effect that unsettles Prospero’s guests to such a degree that most are unwilling to step foot inside the black room. The narrator explains that the blood-red hue twists the charming and fantastical shadows of the former rooms into something wild, alarming, and sinister. The black room also contains an ominous ebony clock which, along with the red Gothic windows, contributes to the sense of unease that purveys the seventh suite. When the clock rings each hour, its sound is so loud and so distracting that it permeates through every room in the estate, causing everyone to fall silent until the chimes cease. People stop talking, the orchestra stops playing, and the dancers stop waltzing as if in a “confused revery or meditation.” 

When the clock is not sounding, and while the black room is left neglected, the remaining six rooms are so lovely that they seem to be filled with dreams swirling among the revelers. However, while the estate is indeed beautiful, it is also strange. Prospero’s guests are so struck by the estate’s unconventional design and decor that many of them feel that they need to closely inspect their prince and savior to be sure that he is not mad. The curiously colored rooms, the lack of traditional lighting, and the fantastical shadows that dance across the castellated abbey create a dreamlike and otherworldly state that none of Prospero’s 1,000 companions have ever experienced before. The narrator discloses that the overwhelming, unnatural, and gaudy splendor is so extreme that it occasionally borders on the grotesque.