Scarlett Fisher is an average California teenager. She likes hanging out with her friends and talking on the phone. She does all right at school, and she's made the best of her parents' divorce. But in one way, she's special: on her fifteenth birthday, a fast-moving plague wipes out everyone she’s ever known, yet somehow it passes her by.

Her family dead, alone in a corpse-strewn metropolis, she has no choice but to survive. She needs food, shelter, a safe place to sleep. She discovers that an ordinary girl is capable of extraordinary things, and that she's more resilient than she imagined. Even so, she wishes more than anything that she could just find another survivor.

Unfortunately for Scarlett, not everyone who survived the plague is looking for companionship. And she’s about to find out just how difficult survival really is.