How do you rid the Earth of seven billion humans? Rid the humans of their humanity.
Surviving the first four waves was nearly impossible. Now Cassie Sullivan finds herself in a new world, a world in which the fundamental trust that binds us together is gone. As the 5th Wave rolls across the landscape, Cassie, Ben, and Ringer are forced to confront the Others’ ultimate goal: the extermination of the human race.
Cassie and her friends haven’t seen the depths to which the Others will sink, nor have the Others seen the heights to which humanity will rise, in the ultimate battle between life and death, hope and despair, love and hate.
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Following the first phases of the invasion revealed in Rick Yancey's breakthrough book, the world of The 5th Wave "is a clock winding down," (p.1) with each tick of which, and every tock, what little hope there is left is lost.
No one knows exactly how long the last remnants of humanity have, but they're looking at a matter of months, at most... unless someone, somewhere, can conceive of a means of driving the aliens away—aliens who, as the big bad of the series says, have nowhere else to go.
"You've lost your home," Vosch asks The Infinite Sea's central character—not Cassie, as it happens—to imagine. "And the lovely one—the only one—that you've found to replace it is infested with vermin. What can you do? What are your choices? Resign yourself to live peaceably with the destructive pests or exterminate them before they can destroy your new home?" (p.201)