1 Woman. 1 Day. 100 Miles. And an attempt to prove that “impossible” is just a word. Ashley Lindsey’s mission to finish the Western States 100 Mile Endurance Run in California’s Sierra Nevada mountains—the world’s oldest and most prestigious trail race from Squaw Valley to Auburn—is documented in this film where she batters bitter cold, stifling heat, and her own mental and physical limitations along the way.