Marshal Wyatt Earp kills a couple of men of the Clanton-gang in a fight. In revenge Clanton's thugs kill the marshal's brother. Thus, Wyatt Earp starts to chase the killers together with his friend Doc Holliday.
During a Space Shuttle mission a satellite rams a unidentified flying object. The UFO afterwards performs an emergency landing in the deserts of Arizona. However the White House denies it's existence because of the near presidential elections. The UFO is brought to the secret hangar 18 and the accident is claimed to incompetence of the astronauts Bancroff and Price. But the two fight against this and try to hunt down the UFO.
Beethoven is back -- and this time, he has a whole brood with him now that he's met his canine match, Missy, and fathered a family. The only problem is that Missy's owner, Regina, wants to sell the puppies and tear the clan apart. It's up to Beethoven and the Newton kids to save the day and keep everyone together.
Some college students manage to persuade the town's big businessman, A. J. Arno, to donate a computer to their college. When the problem- student, Dexter Riley, tries to fix the computer, he gets an electric shock and his brain turns to a computer; now he remembers everything he reads. Unfortunately, he also remembers information which was in the computer's memory, like Arno's illegal businesses..