What is the main point of the story?

In Pax, by Sara Pennypacker, a boy named Peter and the fox he raised must grow up in a hurry when they are separated. It was shortly after Peter's mother’s death when he adopted the orphaned red fox kit that he named Pax. Peter’s father volunteered to go to war five years later. Before he left, he forced Peter to leave Pax in the woods. When Peter realized he had betrayed Pax, he went on a physical and emotional journey to find his friend. As the story follows Peter's steps along the way, it addresses such issues as conquering one’s anger, the effects of war, and the coming of age for both Peter and Pax.