Have you ever been vaccinated against a particular disease? As children, Pearl Kendrick and Grace Eldering both suffered from whooping cough, a life-threatening illness. As adults, they worked together to create a revolutionary vaccine that saved thousands of lives each year. Eldering and Kendrick worked in a Michigan lab at a time when whooping cough was spreading around the country. Determined to stop the illness, the pair tested bacteria late into the night. Soon their new vaccine was helping children across the country. But how did they get there? Find out how Eldering and Kendrick's passion for fixing a problem led them to create an important vaccine.