This is a 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.

Growing up in the brutal care system of South Africa, Paul Sinton-Hewitt had a lonely, difficult childhood. Yet he found solace in running - a simple pleasure that taught him resilience and offered a young boy a sense of self-worth.

With dogged determination, Paul built a stable family life for himself and eventually settled in the UK. But by 2004 he was struggling to hold it all together. He'd lost the successful career he'd worked so hard for, his marriage had broken down, and now a devastating injury threatened to cut him off from the running club which had been a lifeline.

In search of connection and purpose, Paul 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.