When their plans for a nature trip go awry, Polly and boyfriend Seth decide to check into a motel. On their way, they’re carjacked and kidnapped by low-rent crooks Dennis and Lacey, who take the victims and their SUV to a nearby gas station. Along the way, they encounter an increasingly terrifying horde of parasites, and if any of them intend to survive, they’ll have to outsmart the deadly organisms.

A depressed housewife who learns her husband was killed in a car accident the day previously, awakens the next morning to find him alive and well at home, and then awakens the day after to a world in which he is still dead.