A major event is when the prince decides to lock himself and all of his courtiers in his castle to prevent the Red Death from reaching them.
One of the first important events (after the plague itself), is the beginning of the revelry. Prince Prospero knows that his kingdom is in trouble. A terrible plague called the Red Death is ravaging his people. Instead of doing something about it, he takes all of his nobles and followers and they lock themselves in his castle. They think they can protect themselves from the plague within, as everyone dies without.
When his dominions were half depopulated, he summoned to his presence a thousand hale and light-hearted friends from among the knights and dames of his court, and with these retired to the deep seclusion of one of his castellated abbeys.
This incident is important because it demonstrates the prince’s greed and selfishness. It also shows that the only people he values are his important friends. The people of his kingdom mean nothing to him.
As a result of the prince’s actions, the revelers have a few days of fun. Yet their masquerade is not without turmoil, as an unexpected guest in the form of Death comes calling and interrupts the fun—killing everyone inside. The message is that no one can escape death, no matter how rich.