Professor Joshua Copeland is driving home to be with his family on what is gearing up to be one hell (maybe even literally) of a night. Storms have been raging for a week straight, tsunamis threaten coastal states, meteors are approaching the planet, a disease is infecting the brain causing savage behavior, and fish are swallowing children whole. Fish. Joshua arrives just in the knick of time to get his wife Karen, and his children Dana, Matt and Brianna, to weather out the category five hurricane sweeping…the entire country.
Having survived the night, the Copelands go about cleaning up the wake of the disaster, which mostly involves picking up dead fish from their yard. Sheriff Earl Dodkins pays the Copelands a visit. He's hunting down his missing nephew Clark Becker, while trying to get a shell-shocked wanderer some grief counseling. That night at dinner, the Copelands are visited by none other than Clark, begging for food. When he's eaten his seconds, he tries to wash it down with the body and blood of the Copeland family — wait, what? Turns out, Clark's become a "Skin Walker", a kind of demon that takes possession of a human body to shake its insatiable hunger. Karen fends Clark off long enough for Matt to shoot him in the chest.
While the rest of the family start battening down the hatches, Karen heads to the local police station looking for some answers (and backup). She's ambushed by crazed prisoners, and escapes with her life and a shotgun…score! The next morning, Brianna is abducted by another dangerously deranged creature, and it literally swoops her off her feet - and flies off with her. The remaining Copelands load up the RV and set out to find her.
Brianna and her captor Skin Walker have landed in a forest somewhere. When the Skin Walker wakes up, hungry, he lunges for Brianna, accidentally impaling himself on a branch. This is Brianna's cue to exit. She emerges on a street, and is picked up by Sheriff Dodkins and his deputy, who have both gone off the deep end and killed their sergeant. She's definitely in good hands. While her family is headed to Yakima (where FEMA has set up a makeshift sanctuary), Brianna is getting dragged by hungry, feverhead (feverhead being a word for those who have caught a plauge that makes them insane) cops into a restaurant that's been taken over by a band of bikers. With guns. Brianna gives the bikers a heads up, and they're able to get the drop on the coppers. To return the favor, the leader of the pack offers to give Brianna a ride to Yakima so she can reunite with her family.
The Copelands arrive at Yakima, and are given an immediate check up at checkpoint. Are they bleeding from the mouth? No? Good: they're not feverheads. But how about this van filled with howling, crazed, gun-toting yahoos? Feverheads? You bet. Soon after, an army guns them down. Shortly after Brianna arrives to Yakima, she's greeted not by her family, but by a meteor that makes a memorable first impression with Earth. Taking shelter beneath a bus, Brianna fails to connect with the family Copeland, who have gotten back behind the wheel of their trusty RV on the search for their daughter.