One day, the power goes off and the world falls silent. And in two very different parts of America, two very different nightmares are about to begin.

In Manhattan, Elizabeth and her brother Henry are all alone in their parents' apartment. Looking out the window, they can see the carnage slowly spreading through the city. But as hopes fade for their parents to come back, Elizabeth and Henry discover that dangers might already have entered the building.

Meanwhile, in Oklahoma, Thomas and his family live on an isolated farm. They too have noticed that something has changed, and a chance encounter on a deserted road leads to a moment of pure horror. An infection is spreading, and soon more victims begin to fall.