Anarchy by Megan DeVos

The world is different now.There are no rules, no governments and no guarantees that you will be saved . . .Rival factions have taken over, fighting each other for survival with no loyalty to anyone but their own.At twenty-one, Hayden has taken over Blackwing and is one of the youngest leaders in the area. In protecting his camp from starvation, raids from other actions and the threat of being kidnapped, he has enough to worry about before he finds Grace.The daughter of the head of the rival camp, Greystone, Grace is slow to trust anyone-much less the leader of those she has been trained to kill . . .This is danger. This is chaos. This is anarchy . . .