Katrina is a single mother who travels across the country with her young daughter Clara to start a new life. But their car breaks down in the middle of nowhere. While Katrina is changing the tire, Clara wanders off the desert road and is bitten by a venomous rattlesnake. Desperate to save her daughter's life, Katrina accepts the help of a mysterious woman. The woman miraculously heals Clara, but asks Katrina to kill a stranger as compensation. To prevent her daughter from being put in danger again at sunset, Katrina must quickly resolve a moral dilemma: who should live and who should die?