Epidemics, floods, droughts - for sixteen-year-old Lucy, the end of the world came and went, taking 99% of the population with it. As the weather continues to rage out of control, and Sweepers clean the streets of plague victims, Lucy survives alone in the wilds of Central Park.

But when she's rescued from a pack of hunting dogs by a mysterious boy named Aidan, she reluctantly realizes she can't continue on her own. She joins his band of survivors, yet a new danger awaits her: the Sweepers are looking for her. There's something special about Lucy, and they will stop at nothing to have her.