Hannah Ashton wakes up to silence. The entire city around her is empty, except for one other person: Leo Sterling. Leo might be hottest boy ever (and not just because he's the only one left), but he's also too charming, too selfish, and too much of a disaster for his own good, let alone Hannah's.

Stuck with only each other, they explore a world with no parents, no friends, and no school and realize that they can be themselves instead of playing the parts everyone expects of them. Hannah doesn't have to be just an overachieving, music-box-perfect ballerina, and Leo can be more than a slacker, 80s-glam-metal-obsessed guitarist. Leo is a burst of honesty and fun that draws Hannah out, and Hannah's got Leo thinking about someone other than himself for the first time.

Together, they search for answers amid crushing isolation. But while their empty world may appear harmless . . . it's not. Because nothing is quite as it seems, and if Hannah and Leo don't figure out what's going on, they might just be torn apart forever.