1970s, in the Texas panhandle. Troy Falconer returns home after years of working as a solitary car thief to help his younger brother, Harlan, search for his wife, who has run away with the little money he had. When they steal a station wagon for the journey, the brothers accidentally kidnap Martha Zacharias, a Mennonite girl asleep in the back of the car. Martha turns out to be a stubborn survivor who refuses to be sent home. The trio attempts to escape across the Mexican border, pursued by the police and Martha's vengeful father.