Narrated by Academy Award® winner Matt Damon, the film chronicles the story of the iconic Boston Marathon--from its humble origins with only 15 runners to the present day. In addition to highlighting the local Patriots Day race as the oldest annually contested marathon in the world, the film showcases many of the most important moments in the race's history. Among these monumental moments are the tragic events of 2013 bombings, and the preparations for and eventual running of the 118th Boston Marathon one year later, when runners and community gather together "Boston Strong" for what would be the most meanigful race of all.