Beware of the Dog (1964)

While trying to move into their new home, the Woodley family is deterred by a snarling Great Dane named Junia. The Woodleys finally move in, after young David Woodley gains the dog's trust with love and patience. Junia, who rather barks than bites, becomes David's best friend until Major Craddock arrives, claiming the dog is his. Therefore, David tries to hide with Junia, but both are found and David has to give her up. Meanwhile, Michael and Susie, who are David's new friends, are searching for a dog thief and suspect the Major. Are they on the right track?