This is the story of a simple idea that turned into a global movement. This is the story of parkrun, told for the very first time from the man who started it all. Paul Sinton-Hewitt's love for running was forged through a difficult childhood. It gave a young boy a sense of freedom and helped him build a life for himself. Years later when he suffered a serious injury that held him back from competitive running, Paul felt he'd lost all purpose in life. That's when he came up with a simple idea. He would start a weekly time trial run every Saturday morning in his local park. There would be no winners or losers, it would always be free and Paul would be there every week - even on Christmas Day - whether or not anyone else came. Little did he know that from just thirteen runners on that first Saturday, parkrun would grow into a 10 million strong community across five continents. Twenty years on parkrun continues to grow, bringing together people from all walks of life in search of health, happiness and community. Filled with hope and optimism, One Small Step is a powerful affirmation of how coming together in simple ways can change our own lives and might even change the world.