It's summer again. The sun is bright and strong and easing into long, warm, lazy days filled with relaxation and gathering of friends and family. It is a time of fun and play, picnics, and baseball in the park.

But it was not to be.

Swimming pools were empty. The parks were deserted, and as the hot summer days simmered on, so too did a lingering dread. This fear descended into fall like a shadow remnant after summer had long disappeared. A mysterious illness was sweeping across the globe, and no one knew what to do or how to protect themselves.

This unexplained summer plague came to be called polio, and soon there would be much trial and error, and finally a race to develop a safe and effective vaccine to save the world.