Of course, not all humans are happy to have the zhree on their planet, and the main resistance is Sapience, which has now splintered into the Human Action Party, a political group working to promote humans, and True Sapience, a more violent/extreme extension of terrorists. Most of Sapience's former activities were terrorist in nature with bombing buildings, assassinating leaders, and killing Exos they find. Exos are seen as the enemies and "pets" of the zhree (also called shrooms). However, they are independent people who work in harmony for the most part.
Donovan is a soldier-in-erze, who lost both of his parents in the first book. He has been called upon by the zhree to participate in their discussions to decide who will follow his father as the Prime Liaison, and this has given him unwanted political capital. Add to that, the girl he loves is in Sapience, and Donovan is carrying a lot of weight. Everything is about to change when the Mur decide to evacuate Earth and take some of the healthy, young, hardened Exos with them. Lines are drawn and violence and tension on Earth escalate.
Donovan has some tough decisions to make as the sides are blurred and what is best for humans and Earth becomes even murkier. This sequel is even more action-packed than the first and gives more insight into the aliens and world created here. I really liked the additional background and world building in this book, but it does get pretty slow in the middle. However, I liked how well everything was wrapped up and how things are changing on Earth.
This series has some interesting insights into colonization and immigration that I think are really worth talking about- there's no clear right and wrong here, and how it's handled is really fascinating. This is something you don't often see in a YA series. I really enjoyed this conclusion to the duology and highly recommend it for YA readers of all ages!