An unlikely friendship. A dangerous voyage. A story about what it means to be human. Humans went extinct thirty years ago. Now the world is ruled by machines. And twelve-year-old robot XR_935 is just fine with that. Without humans around, there is no war, no pollution, no crime. Every member of society has a purpose. Everything runs smoothly and efficiently. Until the day XR discovers something impossible. Until the day XR discovers a twelve-year-old human.