Overbearing mom, Jackie, travels cross-country to be with her son, Angelo, after he drops out of college to become a surfer. She meets a surf instructor who convinces her to try to accept her son's wishes and allow him to follow his dreams.
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.