Since he was a young colt, Joey has been loved and cared for by Alber, a young English farm boy. At the beginning of Wold War I, Albert's father sells Joey to a captain in the cavalry. The boy is devastated and promises Joey that someday he will find him. Joey experiences army life and the disastrous consequences of a cavalry charge into machine guns. He is captured as a prisoner of war and becomes a hospital cart transport horse for the German army.