In the 1890's a team of physicians and scientists discovered the cause of bubonic plague, a bacteria they named Yersinia Pestis. It was assumed for most of the 20th century that Yersinia Pestis also caused the infamous Black death of the 14th century. But starting in the 1980's a number of experts started to question this assumption. Does this theory still stand up to scrutiny? Tune in and find out how ebola, basilisk potions, and the top speed of a rat all play a roll in the story.