The Newton family from the first two Beethoven movies are on vacation in Europe, but do plan to join a Newton family reunion, and to make sure one of their family members definitely makes it, they ship him to travel to the reunion with George Newton's brother Richard. Guess which family member it was? That's right, Beethoven! The giant dog follows Richard Newton and his family of a nagging wife and two bratty kids, as they hit the road to California in a huge, shiny, and expensive RV, equipped with a DVD player. Following them, are two bumbling crooks who have hidden some secret codes on a DVD that they figure no one in the world will buy, but someone does: Richard. So now they have a DVD holding top secret information, and the crooks must get it back.