On Cate Mortensen's seventeenth birthday, her family is scattered in a fight for survival, and she and her sister Melody are catapulted headfirst into a world where their phones are just hunks of plastic, they must scavenge for every bite, and they sleep with weapons in their hands. Traveling alone, and then not so alone, they follow the route their family planned to Alcatraz Island where the hope of safety and a real life awaits. After more than a year on the road, Cate has found three things to be true. One: Zombies are a thing now. Two: Not all zombies are just zombies. Three (the game changer): Cate is immune to the infection.