Beethoven’s 4th

Richard checks in with his children Sara and Brennan before school, and Beethoven remains under their care for relatives. The parents are eager to get rid of the dog, setting up the central conflict of the story. This morning establishes the family's routine and the tension around Beethoven's place in the household.

Beethoven begins obedience training led by a former army sergeant. Brennan meets a girl named Hayley during the lessons, while Sara grows attached to the dog. On the same day, Beethoven dramatically destroys the obstacle course and even knocks the sergeant over with a leash, highlighting his unruly energy.

Meanwhile, the wealthy Sedgewick family owns a pampered look-alike dog named Michelangelo. The two dogs end up in the same neighborhood as chaos unfolds, and Brennan and Sara mistake Michelangelo for Beethoven and bring him home. The real Beethoven is mistaken for Michelangelo and is grabbed by Jonathan Simmons, the Sedgewick family butler, and taken to the Sedgewick mansion.

At dinner at the Sedgewick mansion, Michelangelo reveals his different behavior: he wipes his feet on the welcome mat and folds the napkins with his teeth. He bolts Simmons to the ground to get a piece of turkey, signaling his true identity to the family. That night, Beethoven hears Madison whimpering from a bad dream and comforts her, showing the bond between the dogs and Madison.

At the next obedience class, Michelangelo finishes the entire new obstacle course, leaving everyone astonished as the sergeant announces the course. The crowd cannot tell that the dog is actually Beethoven in disguise, which deepens the confusion. The performance sets up the looming reveal and the contest between the two dogs.

Beethoven ruins a dinner party when a man named Nigel tries to dognap him, causing chaos and embarrassment for both families. The incident increases the sense that something is wrong with the dogs' behavior. The party's disruption foreshadows the growing misperceptions about which dog is which.

A therapist explains that Michelangelo's symptoms may stem from Martha's self-centered focus, suggesting the owners' neglect is influencing the dog. The diagnosis implies that the dogs mirror their owners' dynamics more than any single animal's will. Richard begins to imitate Beethoven's chaos in an attempt to provoke the dog back toward obedience.

Richard's concern about Beethoven drives him to emulate the dog's wild antics, including drinking toilet water and chasing the mailman. The family atmosphere becomes tenser as their efforts to fix Beethoven start mirroring the dog's chaos. The lines between pet and owner blur as both households slip further into disorder.

Michelangelo begins behaving more like Beethoven, and the two dogs' personalities increasingly resemble each other. The confusion escalates as it becomes harder to tell which dog is which. This switch-like behavior foreshadows the upcoming climax at the obedience graduation.

Nigel, revealed to be Simmons' sidekick, kidnaps Beethoven and locks him in a warehouse for ransom. Michelangelo remains at large with the Sedgewicks, maintaining the charade. The escalation increases the stakes for both families as the truth about the dogs edges closer to surfacing.

Beethoven breaks out of captivity and secretly switches places with Michelangelo at the obedience graduation. The real Michelangelo is discovered by the Sedgewicks, and Simmons and Nigel are arrested by two FBI agents. The Newtons' Beethoven is located by them and graduates, tying together the competing narratives.

The Sedgewicks and the Newtons finally meet at a fork in the road, each with their dog, but neither learns about the switch. The film closes with the dogs sharing a bond across the confusion and both families moving forward with their paths.