It began as just another day for David Spires and his wife Tracy: coffee, breakfast, and getting the kids ready for school. Then the bottom dropped out of civilization.

The world ends not with a bang or a whimper, but with a dizzying downward spiral. Instead of the rat race of commuters scurrying to beat the clock, humans are now packs of animals reduced to snarling primitives.

David, Tracy and their daughter Emily, along with fellow survivors, leave Los Angeles for the safety of the country where fewer people means fewer primitives. But as they venture farther away from the city, they realize an unnatural force is at work. Civilization didn't just fall apart...it was overtaken by an ancient evil that was present before the first cave paintings. Human history has no formal record of it, but the dark presence that's fueled nightmares since time began has crept out of the shadows...and its influence is growing.