During World War II, Japan's biological warfare research group, referred to as Unit 731, carried out some of the most inhumane research experiments ever recorded. They also supplied the biological weapons used in the most destructive attacks in human history, killing tens of thousands of Chinese civilians. After the war, the Soviet Union tried, convicted and imprisoned several of the researchers as war criminals. As documentary filmmaker Paul Johnson reminds us, the United States instead made a deal with the Unit 731 leaders under their jurisdiction, agreeing not to prosecute them in exchange for the data they had developed from their human experiments. Johnson will discuss what he considers to be one of the darkest chapters of Cold War realpolitik.