Courage of Lassie

Stars Lassie as Bill, a pup who's been separated from his mother. At first, he has no one to love except other animals. One day, he's found by a young girl, Kathie, who adopts him for her own. But a car accident separates the two of them. Bill becomes part of a WWII K-9 unit until battle fatigue overwhelms him. He turns vicious and has to be rehabilitated.