The 5th Wave is a novel by Rick Yancy. In this novel, aliens have begun an invasion of Earth that began with an EMP pulse that destroyed everything electronic on Earth, then massive tsunamis that destroyed the coastlines, and then a plague caused by a modified Ebola virus that wipes out billions. Then the fourth wave consists of human-alien hybrids designed to kill unsuspecting survivors. Now Cassie, Ben, and Sammy find themselves becoming the weapon in the fifth wave.
