As the "Red Death" was killing everyone in town, Prince Prospero invites his wealthy friends into to his castle to try to escape the "Red Death" leaving the poor people to slowly die with the plague in them.
The chiming of the clock keeps interrupting the party and it's making the Prince and his guests feel uncomfortable and scared cause they know something is going to happen after the twelfth.
In the seventh room, the ebony clock keeps chiming throughout the castle, interrupting the party and the clock chimes every hour and with each hour something bad is coming.
The Prince gets mad that this hooded figure has dressed up as the "Red Death" to make fun of it in front of the Prince. The Prince's guests are frightened by this figure who claims to be "The Red Death".
The Prince tries to kill the hooded figure with his dagger, but it fails because "Red Death" infects the Prince with the plague and eventually the Prince dies in the seventh room.
"The Red Death" goes back to the other guests to finish them off cause they were trying to hide away from the plague but they couldn't escape or hide away for long.