Danny Mitchell (Ted Donaldson) misses his deceased mother and is upset that his father (Conrad Nagel) is remarrying. His stepmother, the kindly Ann (Margaret Lindsay), struggles to connect with the boy. One day, Danny stumbles upon a solution to his loneliness when he encounters his neighbor's dog, Rusty, a vicious German shepherd trained by the Nazis. Danny adopts Rusty and attempts to rehabilitate him, while Ann works on forging a closer relationship with her stepson.