Summary from Goodreads:
The race to the Still Blue has reached a stalemate. Aria and Perry are determined to find this last safe haven from the Aether storms before Sable and Hess do--and they are just as determined to stay together.
Within the confines of a cave they're using as a makeshift refuge, they struggle to reconcile their people, Dwellers and Outsiders, who are united only in their hatred of their desperate situation. Meanwhile, time is running out to rescue Cinder, who was abducted by Hess and Sable for his unique abilities. Then Roar arrives in a grief-stricken fury, endangering all with his need for revenge.
Out of options, Perry and Aria assemble an unlikely team for an impossible rescue mission. Cinder isn't just the key to unlocking the Still Blue and their only hope for survival--he's also their friend. And in a dying world, the bonds between people are what matter most.
I'm sad to see this series end, but I'm glad that the end of the novel was not disappointing (expect for one thing that I will not spoil) and I fell back into the world with ease.
Aria and Perry are one of my favorite main characters, like Day and June, but my favorite one of all was Roar, and he was just as amazing in the last book. Plus I read Roar and Liv the novella that is set before the first novel and really enjoyed it.
Five Out Five Stars.