Huge earthquakes cause that massive damage around the world, and most of the human race becoming homocidal maniacs is the apocalyptic world described in "Dark Inside." The first book in this series serves to tell us how the four main characters ended up together. However, it's more than mere boring backstory, and explores and explains each person's situation and motivations, as well as how the events that take place change them. Yes, I know that's the definition of a backstory, but it's a much needed one, is told very well, and the story would have felt rushed and cramped without it. It's in the next book that the four of them explore the dynamics of their group, as well as how to continue staying alive in this new and frightening world.