Ever since the Great Dark pushed the world into chaos, Gordon's singular focus has been keeping his family alive. But survival is growing tougher by the day, just like the cancerous tumor wrapping itself around his wife Meg's spine.Meg is strong - she's fought off the disease once before. It was over a year ago, when there were doctors and hospitals and pharmacies. Now those things are gone, along with so much else. And the battle inside her body is turning against her. Gordon knows that she won't survive without the cancer medicine that saved her the first time. Medicine that's in a distant and deserted city, out in the darkness.He's heard the stories of a dangerous new landscape, with fearless wild animals and bands of violent outliers. Yet Gordon has to try, even though the only allies he can enlist to help him are his 15-year-old twins, Jessica and Henry. And they may be too young to provide any help at all. But what Gordon starts to see on their journey is that his kids are more gifted than he's ever noticed. They're clever and resourceful, adaptive and resilient. And as the three of them get closer to the city that holds the medicine, they find themselves in the midst of a new war. A war against the hackers who destroyed the world's technological infrastructure and rebuilt it for their own design. And Gordon begins to realize that his children may be the only hope that civilization has left.