Run

Haylee, has been on her own for a while. Her family taken away from her or murdered. One day she's going about her new normal when she runs into a boy, Jameson. He too has no family left. He annoys her and they head off to find a group of people in a "Safe Haven" where she'll accompany him on his journey- more like make sure he lives to get there. And like everything in life, things don't go as planned.
(Listed as mature for the particularly violent parts.)