Requiem (Delirium Series #3) by Lauren Oliver

The third and final book in Lauren Oliver's powerful New York Times bestselling trilogy about forbidden love, revolution, and the power to choose. Now an active member of the resistance, Lena has transformed. The nascent rebellion has ignited into an all-out revolution, and Lena is at the center of the fight. After rescuing Julian from a death sentence, Lena and her friends fled to the Wilds. But the Wilds are no longer a safe haven. Pockets of rebellion have opened throughout the country, and the government cannot deny the existence of Invalids. Regulators infiltrate the borderlands to stamp out the rebels. As Lena navigates the increasingly dangerous terrain of the Wilds, her best friend, Hana, lives a safe, loveless life in Portland as the fiancee of the young mayor. They live side by side in a world that divides them until, at last, their stories converge.