Quahog is in the grip of an unusual heat wave and, not having air conditioning, the Griffins are suffering. Peter learns of an upcoming dog show offering a top prize of $500, which he sees as the perfect way to be able to buy an air conditioner. He persuades a reluctant Brian to participate. Brian performs his tricks at the dog show. Peter puts a bone biscuit on Brian's nose; finding this demeaning and becoming angry, Brian refuses to "perpetuate the stereotype of the 'good dog'", as well as Peter saying he is embarrassed that Brian would not comply. Brian subsequently exits in a huff.
On the way home, Peter and Brian argue until Brian gets out of the car. The police give Brian a ticket, for which Peter has to pay $10, for violating the local leash law, which only widens the rift between Peter and Brian. Another argument ensues and Peter mentions that he found Brian on the road as a stray dog. Angry that Peter brought that up and becoming more angry when Peter then demands that Brian stop being a bad dog, Brian leaves the house, whereupon he is treated cruelly by the community, and is (ultimately) forced to sleep at the bus shelter. Peter buys a new cat which turns out to be mischievous and abusive; the family gets rid of it and searches for Brian. By the time Peter decides to apologize to Brian, Brian has been kicked out of a restaurant and a public store and chased by the police when he was found drinking from a water fountain. Brian becomes homeless, having actually attacked a man on the street for treating Brian as a drunkenhobo and for not believing that Brian was a good dog. He is subsequently taken away by the police and awaits his death sentence via a lethal injection.
A social worker announces to Brian and the rest of his family that he is sentenced to be put down, which shocks the whole family. While Peter works on Brian's appeal, Brian decides to study the laws as much as he can and goes to court to defend his own case, and finally gets the chance to plead his case. During Brian's parole hearing, he references the court case Plessy v. Ferguson, but unfortunately for him, the city council believe that it's stupid to listen to a dog. Just when he is about to be dismissed, Peter steps in and delivers a last-ditch emotional appeal on his behalf. The city council members hearing the case are still not on Brian's side, as they still believe that it's stupid to listen to a dog, but Peter promises to give them each $20, which convinces them to free Brian. The charges against Brian are finally dropped and the town shows him new respect, allowing him to finally drink out of a water fountain, showing his status to be the same as that of the other citizens of the community. The family returns home. After Stewie, in an unusual display of respect towards Brian, bows ever so slightly towards him, Brian and Peter are left alone. Brian licks Peter's face in an endearing dog gesture, and threatens to kill him if he ever tells anyone about it.