By pressing a button, Mr. Burns by accident releases a radioactive cloud over Springfield. Burns Manor is the only building that's still above the radioactive cloud, so every citizen of Springfield must live in his mansion.
One week prior to Mr. Burns releasing a radioactive cloud, filming for "Joe Surprise" is taking place, where Smithers is Springfield's most eligible bachelor, and Ruth Powers, Miss Hoover, Lurleen Lumpkin, and Princess Kashmir as the four women out to marry Smithers. However, Smithers (due to his sexuality) is not comfortable with the situation, although Declan Desmond agreed to film the show at the Springfield Nuclear Power Plant. Desmond is informed that the show "Joe Surprise" has been canceled, and that the network is looking for "real-life idiots" to make a new show. He is about to leave when Homer falls through the ceiling with pails of nuclear waste, which Homer spilled and created a hole. This gives Desmond an idea for a new show.
Mr. Burns wants Homer to do something stupid, but instead Homer hits several buttons that cause the Nuclear Plant to save money. Burns forces Homer aside and messes with the controls, causing a radioactive cloud to release over Springfield. Judge Snyder finds Burns guilty of making Springfield uninhabitable, and sentences Burns to house everyone in Springfield until the cloud goes away. Declan Desmond decides that having everyone living in Burns' Manor would be great for a TV program.
The Simpson family is staying in Burns' game room. Comic Book Guy discovered a secret cave underneath the mansion, which has been decorated to be his secret sanctuary. Professor Frink is living in Burns' hunting trophy room, which has his animatronic skeletons inside. Frink accidentally causes them to activate, chasing everyone around the building. Principal Skinner is caught in a trap set by his mother, turning Skinner into a human pinata. Captain McCallister set up his boat in Burns' pool, which contains barracuda (Homer finds this out when they attack him). Kent Brockman decides to do his own show, called "Kent's People," causing a riff between him and Declan Desmond. Burns begins rolling blackouts and turning off power on the weekends to save money. Later that night, everyone is unable to sleep due to Otto's guitar making lots of noise. Chief Wiggum sends in Willie to play the bagpipes in order to get Otto to stop.
Fast forward to the present day, and everyone is waiting to use the bathroom. The water supply has run out, and Homer suggests using the pool water (which causes the barracuda to attack him again). Everyone gets angry at Burns and Burns tells Smithers to release the hounds. However, the hounds are thirsty due to the lack of water and unable to chase everyone off. Everyone turns into an angry mob with pitchforks and torches, forcing Burns and Smithers to flee into the tower, with Burns changing into a Marie Antoinette disguise. However, he is fooling no one. He throws cake to the mob below, but the plan backfires on Burns as everyone now has the energy to climb the tower. Burns pushes Smithers off the tower, and Snake sets the base of the tower on fire. Lisa, with Professor Frink's help, determines that the radioactive cloud is actually a series of fog machines producing aloe vera-based mist. Declan Desmond reveals that he faked the whole "radioactive" cloud incident to get everyone to live together. Everyone is able to go home, but Burns is angered that Desmond's plan almost got him killed and Burns' Manor burned down. To make it up to Burns, Desmond lets Burns be a judge on "Springfield Idol," where Burns releases the hounds on a contestant.