This episode is a two-for-one in a sense that two major scenarios are Imagined. The Black Plague ravaged Europe in the 13th Century, with death rates 20x that of the COVID-19 pandemic, maybe even double that. It's estimated that 33% of Europe and the Middle East died during the Plague, although two nations (Milan and Florence) where relatively spared. In today's episode, England and Scotland jointly agree to close the British Isles and when they open up the isles 10 years later, 99% of Europe is dead. This results in the Aztec, Maya, and other native American nations eventually colonizing Europe, instead of the other way around.