Hope wasn't made for us

A war took place 100 years before, making the population limited, people in charge chose to make cities with walls enclosing then from the outside world. To keep them safe. This story follows a young girl named Eveyln, she is becoming a nurse and finding herself, but her life is put to a pause as a mysterious outbreak breaks loose making the walls no longer safe, she meets a little girl making her feel more at home, that little girl gets taken and Evelyn is forced to travel with a man she didn't know, putting her trust in him to help her find the little girl.