Returning home with Maggie from errands, Marge discovers that a part of Springfield is now totally destroyed. As Chief Wiggum announces that Bart could be the culprit, Bart says that he wasn't involved at all in the incident. This prompts Marge to follow him everywhere until he confesses. However, Bart seems not to know what Marge is talking about. Marge eventually is fed-up and gives up her plan. It's then revealed that Bart was really the culprit and he plans to create a new incident, but his conscience eventually wins and he finally admits his fault. Wiggum arrests him but allows him to give a hug to Marge.
Meanwhile, Homer learns that Flanders got a new female puppy dog named Baz. Though Homer isn't her owner, he eventually bonds with this dog, ignoring Santa's Little Helper. This saddens Flanders and he decides to give the dog to his neighbor, much to his and his sons' chagrin. However, Homer advises him to keep her since he will be a better owner than Homer, who in Baz's eyes is just another dog with whom she can play.
The end of this episode shows us Santa's Little Helper and Baz preparing to fight in a Far West style.