Judge Reinhold and Julia Sweeney return as Richard and Beth Newton, the harried owners of Beethoven, their faithful but troublesome St. Bernard. Here, Mr. and Mrs. Newton are forced to consider sending Beethoven to live on a farm because of the trouble he causes in the house. The Newton children take action when they hear the news, and begin to take Beethoven to clandestine obedience classes. However, when practicing in the park with him, the children accidentally switch Beethoven with another St. Bernard, who happens to be snooty and well behaved, just like its owners, the wealthy Sedgwicks. Soon, Beethoven is wreaking havoc on Sedgwick manor and the Newtons are puzzling over their dog's apparent personality transformation.