Driven to the edge by the loss of her beloved mother (Laura Dern), the dissolution of her marriage and a headlong dive into self-destructive behavior, Cheryl Strayed (Reese Witherspoon) makes a decision to halt her downward spiral and put her life back together again. With no outdoors experience, a heavy backpack and little else to go on but her own will, Cheryl sets out alone to hike the Pacific Crest Trail -- one of the country's longest and toughest through-trails.