Final answer:
Prince Prospero retreats to his fortified abbey and gathers a thousand friends to escape the red death plague, but their isolation proves futile as the red death eventually infiltrates and kills them all.
Step-by-step explanation:
In response to almost half the kingdom dying of red death, Prince Prospero retreats to his fortified abbey, where he gathers a thousand of his wealthy and influential friends and locks themselves inside to escape the plague. They entertain themselves with masquerade balls and indulge in luxuries, believing they are safe from the red death. However, their isolation proves futile as the red death eventually infiltrates the abbey and kills all the guests.