This is the third book in a science fiction trilogy aimed at YA readers. The first book is in the series is "The Fifth Wave" and the second is "The Infinite Sea."
The general premise of the series is that an alien craft dubbed 'the mother ship' harboring 'the others' is hovering over Earth. Its purpose is to destroy the human population. Thus the aliens unleash one catastrophe after another, killing over 7 billion people. The final strategy of 'the others' is to insert their consciousness (sort of download themselves) into remaining humans so that - not knowing who's human and who's not - people will kill each other.
A brave group of youngsters led by teenagers Cassie and Ben (aka Zombie) are desperately fighting 'the others.' Cassie's main goal seems to be keeping her five-year-old brother Sam (aka Nugget) alive. As it turns out a human - Colonel Vosch - has been co-opted by the aliens and is leading the charge to destroy the human race. Conversely, an alien-human hybrid, Evan Walker, has turned on his own kind and is assisting Cassie and her friends.
In books one and two it's not too clear why the aliens want to wipe out humanity and exactly what they plan to do with planet Earth. In book three, after a lot of action - shooting, knifing, gouging, fighting, killing, double-dealing, burying, bombing, hiding among dead bodies, helicopter hijacking, high-tech shenanigans, and so on - the 'truth' is revealed.
For me the big reveal was a big disappointment. The aliens' goal doesn't fit with things that happened throughout the series and felt anti-climactic and not credible. After spending a good deal of time reading three books I was expecting a denouement that was much more dramatic and interesting.
(view spoiler) Moreover, the premise that the mother ship was ultimately destroyed because the aliens don't understand 'love' is cliche and not believable to me.
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Still, the books are action-packed and have brave likable good guys. There's even a drop of romance. I think a lot of YA readers would enjoy the series.