Jack Murphy and his family need a vacation. This one might just kill them.

After a global crisis causes crops to fail and species to disappear, something even more deadly happens. Masses around the world suddenly become predators, feeding off their own kind. These "Can Heads" grow to such a threat that fences, gated compounds, and SWAT-style police protection become absolutely necessary to live.

After one attack leaves NYPD cop Jack Murphy wounded and his partner dead, Jack takes his wife and kids on a vacation far up north, to the Paterville Family Camp, a fortress-like compound in the mountains where families can still swim and take boats out on a lake.

At first, it's idyllic. There's plenty of food, fun stuff for their children, and another nice young couple with kids of their own. And when the camp suffers a Can Head attack, Jack even helps defend it. He's immediately offered a job in security. His family wants to stay.

But Jack slowly comes to realize that there's something else going on at Paterville Family Camp, and when he makes a gruesome discovery, he will be forced to get his family out, no matter who—or what—stands in his way.