Homer accidentally causes an electrical blackout in Springfield, and the residents begin looting the town's businesses. Chief Wiggum is useless at restoring order, so Homer takes the law into his own hands, starting a private police force, and becoming the 'chief of police.'
During a scorching heatwave, everyone is trying to beat the heat. Springfield Elementary has a great new air conditioner which brings back old students and everyone town is using theirs. That night, Homer plugs in a singing/dancing Santa to try to make the family feel cooler. This action causes all of Springfield to experience a power failure, as the Springfield Nuclear Power Plant is unable to cope with so many appliances demanding power all at once.
Lenny and Carl spark off a massive looting spree after crashing their cars into each other - then a store window - whilst talking to each other on their cell phones. The Simpsons set up chairs on their roof to watch the thievery, and wait for the police to arrive. After accidentally letting slip to the crowds that the police are not prepared to use force, the rioters start to smash up the police car. The next day after the riot, several people complain the town isn't safe and blame the police for not being prepared. Wiggum however just tells the town they should never have started this whole thing.
Homer tracks down the thief of Lisa's dolls, by going to The Wooly Bully -- where he discovers that the suspect was Jimbo. He saves Apu from being robbed and shot, by tossing hot nacho cheese on Snake.
He plans to start a security company, SpringShield, to protect the town -- as the police are now a joke to the townspeople. Homer enlists Lenny and Carl to accompany him. When Mayor Quimby discovers Chief Wiggum trying to shoot a piñata with a shotgun, blindfolded, he fires Quimby and in a blind rage turns all of the town's police duties over to Homer and SpringShield.
SpringShield busts Fat Tony, catching him gluing cotton balls on ferrets to sell to a pet shop, claiming they're toy poodles. A depressed Wiggum sees this on the news and tells Ralph he's done trying. Fat Tony then vows, over the radio, that he and his associates will gun Homer down if he doesn't skip town by noon the next day.
In church, Homer asks for his fellow churchgoers to stand and fight with him, but none are willing - except Flanders, who Homer tells to "Shut up." Lenny and Carl lock themselves in a police cell as they too will not help. Homer becomes very upset that for once he actually enjoyed working but now he's getting killed for it.
Fat Tony meets with his New Jersey associates (comprised of members of the Tony Soprano crew: Christopher Moltisanti, Paulie Walnuts, and Silvio Dante) as well as Johnny Tightlips. They travel to the Simpsons house - Sopranos style - and demand for Homer to come out. Just as the mobsters draw, gun shots ring out. Fat Tony, and two others, drop their guns. More shots ring out and the rest of the mobsters go down, injured.
Homer swears to give his badge to the next guy he sees, Wiggum appears and takes the badge, saying that this is how he got the job the first time. Marge thanks Wiggum for saving Homer, but he says it wasn't him. Homer states that he must have a guardian angel (with a rifle).
The scene shifts to Maggie's bedroom, and she is holding a smoking rifle but quickly hides it under her mattress as Homer and Marge come to check on her. They think she is napping, and "probably dreaming about the time she shotMr. Burns." "She's just like Clark Kent," says Homer. "When there's lots of excitement, she's nowhere to be found." He pulls the blanket over Maggie and walks out. Maggie then opens her eyes and gives a grin to the 'camera'.