Their love and their leadership have been tested. Now it's time for Perry and Aria to unite the Dwellers and the Outsiders in one last desperate attempt to bring balance to their world. The race to the Still Blue has reached a stalemate, but Aria and Perry are determined to find this last safe-haven from the aether storms. Meanwhile, time is running out to rescue Cinder, who was abducted by Hess and Sable for his unique abilities. Out of options, Perry and Aria assemble a team to mount an impossible rescue mission-- because 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.