A wealthy entrepreneur invites a top paleontologist, a paleobotanist, a mathematician/theorist, and his two eager grandchildren to visit his secret island theme park featuring living dinosaurs created from prehistoric DNA.

Adopted by the Newton household's three children, an adorable little St. Bernard puppy grows into 185 pounds of disaster-prone trouble; There's trouble in the heir when Beethoven becomes the proud father of four pups, each one an adorable but mischievous bundle of joy; When two bumbling thieves threaten the safety of his family on vacation, Beethoven sets out to put a bit on the bad guys.