Fallout — James K. Decker

Overpopulation, disease, and ecological disaster were edging humanity toward extinction. Hope arrived in the haan, an alien race that promised us a future.

And what they wanted in exchange seemed so harmless...

Sam Shao has found out too much about the haan, by accident. All humans have to get along with them -- we owe them our lives -- and Sam even counts a haan among her best friends. But the more she learns, the less she trusts them

It doesn't help that the building of new haan colonies seems to be coinciding with a rash of missing persons cases. Sam and her hacker friends are determined to reveal the truth about the haan, before it's too late. The aliens are still promising salvation, and they seem set to deliver, but with things already spinning out of control Sam is confronted with a possibility no one wants to admit -- that what salvation means to humankind and what it means to the haan may be two horribly different things.