"Grandpa Sugar Pill" Gu Fangzhou was entrusted with the mission to develop the poliovirus vaccine. After testing the vaccine on himself, he also involved his young son in children's trials, leading the team to overcome difficulties. To facilitate promotion, he improved the liquid vaccine into a sweet sugar pill, solving storage and transportation issues. After decades of effort, he made China a polio-free country. Even at the end of his life, he said, "Doing one thing in a lifetime is worth it," protecting the health of millions of children with perseverance and dedication.