The terrible crimes of Japan's secret Unit 731 would make anyone's blood run cold. Thousands of people were used as test subjects for the development of biological weapons. The subjects were injected with cholera, typhoid, anthrax and bubonic plague, to be later dissected alive. The unit's ideologist, Shiro Ishii, and most of his associates were never punished. They became practising physicians or scientists. Watch our film to find out why.