In 1940s and ’50s America, polio is as dreaded as the atomic bomb. Some of the world’s best minds are engaged in the race to find a vaccine. The man who succeeds will be a god. But Dorothy Horstmann is not focused on beating her colleagues to the vaccine. She just wants the world to have a cure. Applying the same determination that lifted her from a humble background as the daughter of immigrants, to becoming a doctor, she hunts down the monster where it lurks: in the blood. This discovery of hers, and an error by a competitor, catapults her closest colleague to a lead in the race. When his chance to win comes on a worldwide scale, she is asked to sink or validate his vaccine --- and to decide what is forgivable, and how much should be sacrificed, in pursuit of the cure.