When Sara takes Beethoven to spend summer vacation with wacky Uncle Freddie in an old mining town, the mischievous canine "digs up" the missing clue to a legendary hidden fortune of Rita and Moe Selig. Now everybody wants to be the dog's best friend as his discovery unleashes a frenzy of treasure hunting among the community's cast of kooky creatures. With help from Uncle Freddie and Garrett (a friend or maybe more), Sara and Beethoven try to help uncover a secret that has been in the crazy little town for years.
The Newton family live in their comfortable home, but there seems to something missing. This "hole" is filled by a small puppy, who walks into their home and their lives. Beethoven, as he is named, grows into a giant of a dog... a St Bernard. Doctor Varnick, the local vet has a secret and horrible sideline, which requires lots of dogs for experiments. Beethoven is on the bad doctor's list.