When the family of George Newton (Charles Grodin) decides to adopt a cute St. Bernard puppy, the patriarch soon feels displaced by the dog. Before long, the adorable canine, dubbed Beethoven, has grown considerably, leading to household mishaps. While George's wife and kids dote on Beethoven, it takes time for him to see the pooch's finer qualities. However, Beethoven's life with the Newton family is jeopardized when a scheming vet (Dean Jones) tries to nab the dog for a deadly experiment.