My Side of the Mountain by Jean George is ultimately just about a boy who has to make a decision. He makes one at the beginning of the story, and he makes one at the end. We learn that Sam ran away from his family in New York because he just felt too crowded; though his father is aware that Sam is leaving, he expects Sam to be back the next day. Instead, Sam takes his flint (for fire) along with his "penknife, a ball of chord, an ax, and $40" and he heads to the Catskills.
Sam has many adventures and quite a few harrowing moments, including a blizzard, but he has to work hard to keep himself alive through the winter. As time passes, he is rather surprised to discover that, because he has built himself a home and lives in a kind of community, he is beginning to feel much like he did at home.
I was living in the woods like anyone else lives in a house. People drop by, neighbors come for dinner…I felt exactly as I felt when I was home. The only difference was that I was a little harder to visit out here.
When his family arrives one day--all ten of them--he is forced to make a choice. Will he greet and accept them or will he choose to remain a recluse. That decision is the climax (also known as the turning point) of the story.
While many other interesting and exciting developments happen in the book and we even wonder if Sam will survive, Sam begins the story living in a tree and by the end of the story he has to decide if he is going to keep on living there or go home. That's it.