Days 5 to 8 is the second book in the Mass Extinction Event series, continuing the story of a worldwide apocalypse seen from the eyes of two very different people in two different parts of the US.

Trapped in a ruined city, Elizabeth and her brother Henry try to avoid the dangers that seem to lurk on every street. But even when they manage to get home, they face an entirely different kind of threat. Meanwhile, hundreds of miles away, Thomas struggles to keep his brother alive. First, though, he needs to find out what happened to his father, and he also has to make a difficult decision about his ailing mother.