When a fire breaks out, Homer is trapped beneath an ice sculpture. Santa's Little Helper is turns tail and runs away, leaving the family cat to perform the rescue.
The poor dog is banished from the house. While playing alone outside, Santa's Little Helper toys with a discarded can of Duff beer. A photojournalist snaps a picture, which inspires the Duff Corporation to name the dog as the new mascot. In exchange, the Corporation showers the Simpsons with wealth.
Out of nowhere, the original owner of Santa's Little Helper appears and reclaims the dog. Santa's Little Helper is now miserable, so the Simpsons create an elaborate plan. During a Duff Beer publicity event at the beach, Homer pretends to drown. (In reality, he is merely balancing on a keg of beer.)
Once again, Santa's Little Helper is afraid to save him. The once adoring public is shocked by the dog's cowardice. Meanwhile, Homer is attacked by a giant shark. The shark bites the keg of beer, and gets drunk. The inebriated animal floats to the shore, where the crowd is delighted by his antics. In a burst of inspiration, the Duff Corporation fires Santa's Little Helper and names the shark as the new mascot.
The dog's owner wants nothing to do with him any longer, and the Simpson's family pet is once again their own.