After the 1st wave, only darkness remains. After the 2nd, only the lucky escape. And after the 3rd, only the unlucky survive. After the 4th wave, only one rule applies: trust no one. Now, it's the dawn of the 5th wave, and Cassie meets Evan Walker. Beguiling and mysterious, Evan may be Cassie's only hope for rescuing her brother --- or even saving herself.