Yancey, Rick. The 5th Wave.

The aliens came in four waves, each one a more deadly attack that killed more humans until the dawn of the fifth wave. Cassie’s family survived the first and second wave. Her mother died from the plague that the aliens release killing most of humanity, including her mother. After the fourth wave, her dad was killed and her five year old brother was taken to an alien death camp. Now toting an M-16 and a few essential supplies, Cassie is trying to find her brother and the only one who can help hers a half alien boy and Cassie isn't sure she can trust him..

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