War Horse, a simple story and a great piece of theater

Think of a sixteen year old boy who loves his horse so much that when it's sold to the military at the outbreak of WWI, he lies his age, joins up, and sets out to find him. Of course there's more to it than that, but any story about a boy and his horse (or a girl and her horse such as National Velvet) is a winning combo. Steven Spielberg has already bought the film rights to it.