You Are The Daybreak

Aurora "Rory" Daniels is the general's daughter in a post-apocalyptic world where the new society has built walls the keep out the creatures of death which brought down the world before. They are a system of settlements who exist in harmony, and at the center of their world is the Empyrium, a place where the mostly wealthy holed up when SHTF. they control the money, and the settlements control the goods. Aurora's settlement provides soldiers for security for each other settlement and the empyrium.

Aurora is out hunting one morning when her settlements alarm sounds. She runs home to find chaos within their gates and a hologram from the empyrium. Rebels from one of the settlements have taken the emperor's daughter Trixie and is only giving the settlements a short amount of time to return her before he starts slaughtering them all. Rory hurries to find her dad, and on her way runs into her first Sargent, who agrees to help her get through the chaos in his truck. On the way, they crash into another truck with masked men and a cage in the bed of the truck. The cage is jumbled and a young girl is revealed, and though their vehicle was smoking the men kept driving.

When they reach her dad's bunker they find out these men were the rebels and must have been hiding in their settlement. Having never seen anyone from the empyrium before, they couldn't have known that the girl in the cage was Trixie, the emperor's daughter. Now the rebels must be caught before their settlement becomes the first to receive the emperors wrath. The first Sargent agrees to find them and Aurora won't let him leave without her help. The two set off on a world shaking adventure where they learn more about themselves and the veil is ripped off of the world they thought they knew.