A young couple sinks their life savings into a house that was trashed by a rock group to the extent that it no longer has a main stairway or water. This creates strains on their relationship. Every home owner will recognize some of the situations they encounter.

Barely escaping from nefarious dognappers, an adorable puppy named Beethoven adopts the unsuspecting Newton family — and promptly grows up into 185 pounds of romping, drolling, disaster-prone St. Bernard! Unfortunately, even after proving his canine credentials to mom and the kids, the heroic hound gets nowhere with uptight dad, George (Charles Grodin). But when a beastly veterinarian (Dean Jones) makes Beethoven the target of an unspeakable animal experiment, George becomes the only hope for saving the Newton’s furriest family member.

The Addams step out of Charles Addams’ cartoons. They live with all of the trappings of the macabre (including a detached hand for a servant) and are quite wealthy. Added to this mix is a crooked accountant and his loan shark and a plot to slip in the shark’s son into the family as their long lost Uncle Fester. Can the false Fester find his way into the vault before he is discovered?