Aliens attack Earth in 5 waves, the 1st wave being a permanent blackout of power, setting earth back into the Stone Age. The 2nd wave being a massive tsunami, killing off all coastal cities. The 3rd wave being a plague caused by birds, leaving only the unlucky alive. The 4th wave being humans with activated alien brains. And what's the 5th wave... Well that's what Cassie Sullivan wants to know. As she goes to fulfill a promise she'd made, to return to her brother, she meets Evan Walker, a strange but beautiful boy with a secret he won't tell her. But the closer she gets with Evan the closer she gets to getting her brother and unraveling the secrets of the 5th Wave.