Following the tragic death of her twin sister, Eve enters into the most intense athletic endeavour on the planet: the Badwater 135 Ultramarathon, a 135-mile race through Death Valley, where temperatures reach 54°C. As Eve takes on the unforgiving elements and intense physical and psychological strain of the race, she finds herself pursued by an unknown runner in white, consistently closing the gap between them as they surge through the desert. Trying to outrun the ominous presence, Eve will face the darkest parts of herself and uncover what she is made of.