The film's plot involves Danny Mitchell (Ted Donaldson), a young kid in the American town of Lawtonville, who is grieving over the loss of his dog. He is also struggling to adjust to his new stepmother, Ann (Margaret Lindsay), and has a difficult relationship with his father (Conrad Nagel) - causing him to call on Dr. Banning, a psychiatrist (Addison Richards) for assistance. However, Danny befriends Rusty, a ferocious German shepherd who was brought to America from Germany during World War II. Having worked a police dog for the Gestapo, however, Rusty is ill-tempered and Danny struggles to train him.