"Sideshow Bob's Last Gleaming" is the ninth episode of Season 7.
Sideshow Bob slips away from prison detail, steals an atomic bomb and threatens to detonate it unless the town of Springfield gives up television permanently.
Krusty the Clown begins another episode of his show, but on a serious note; he thanks the children for their contributions to a food drive. However, the cans and boxes of food that were sent in by fans of the show are not being used to feed needy families, but as part of a super-sloppy obstacle course competition (a la Double Dare). Bart and Lisa, as usual, revel in the mayhem and Krusty's abuse of Sideshow Mel.
At the same time, the prisoners at the Springwood Minimum Security Prison are also laughing at the mayhem as well, causing Sideshow Bob to lose his concentration while building a model of Westminster Abbey inside a bottle and ruin his project.
He enters the nearby room where the other inmates were laughing at the hilarious antics of Krusty. After the other inmates remind Sideshow Bob that he used to be Krusty's sidekick, the embittered ex-TV star begins to defame other 'trash TV' shows, all of which he pans as pointless and mindless drivel, until Rupert Murdoch steps in to end Bob's attack on TV claiming "I own 60% of that network!", which is presumably the Fox Network. While on work duty at a local airfield (which is being cleaned for an annual air show), the quality of television programming eats at Bob's mind, and he forms a plan.
Meanwhile, everyone in Springfield, including the Simpson family, are interested and goes to the air show, where the usual antics occur. At the same time, Bob, impersonating an Air Force colonel, gains access into the restricted area of a hangar, where he finds a 10-megaton nuclear weapon.
Col. Hapablap tries to begin the air show, but the signal on the Tyranno-Vision is lost and is then quickly restored while the Tyranno-Vision reveals Sideshow Bob. Bob suggests that life would be better without television, and then threatens to detonate the nuclear bomb unless Springfield gives into his demand to shut down all television broadcasts permanently. Bob also points out that he realized the irony of appearing on TV in order to decry it. Because of this, everyone flees out of the airfield in a panic (Squeaky Voiced Teen: "Stamp your hand for reentry!" but everyone ignores him), while Bart and Lisa are separated from their parents.
Later, while national guardsmen frantically search the base for Sideshow Bob, Mayor Quimby and Col. Hapablap meet each other and they both decide what to do. When Bob is nowhere to be found, Quimby (who is out of options and is running out of time) decides to give in to Bob's ultimatum, despite Krusty's (self-interest motivated) insistence that in a world without television, "the survivors would envy the dead!". As a result, television transmitters are destroyed, television stations hastily plan farewell programs, and Kent Brockman gives a farewell speech, toasting all of the good times that he shared with viewers, such as premium ice cream price wars.
As Bob (whom, we learn, was televising his demands from a stolen Duff Blimp) gleefully celebrates the success of his plan (but also rues the fact that he didn't make more demands, including one for some "decent local marmalade"), Krusty is determined not to give in to his former co-star's demands (if he can stay on the air, he'd have 100% of the audience), so he takes refuge in a civil defense shed and heavily improvises a show including The Stingy and Battery Show after turning on the transmitter. Bob finds out about this and is outraged; later resignedly remarking that it ultimately was a failure as Krusty's slapdash show could "have come from the laziest Hollywood hack".
Eventually, Bart and Lisa find their way into the cockpit of the Duff Blimp, where Bob, having lost his patience, tries to detonate the bomb. However, the bomb was actually a dud and no damage is done.
Bob, outraged that the nuclear bomb didn't destroy Springfield, takes Bart hostage and puts a knife against his neck after landing the blimp. However, Lisa manages to sneak away and creates a message announcing Bob's whereabouts. When Chief Wiggum tries to arrest Bob, the convict just laughs and takes Bart to a hangar, where he attempts to steal a Harrier jet (which the Air Force intended to use for a war the next day), but ends up crashing it into a ditch shortly after the starting point, to which Bob then steals the original Wright Brothers aircraft (which had been an exhibit at the air show), making the commanding officer upset as "the Smithsonian's going to hand [the Colonel's] ass on a platter" as a result. Just then, two Air Force F-14s take off to intercept Bob. However, they overshoot the Wright Brothers' plane and the pilots suggest they get out and walk.
Bob, holding the knife blade to Bart's neck (noting that Bob was once again attempting to kill Bart), plans a kamikaze mission by crashing the plane into the civil defense shed where Krusty is hiding. He flies towards Krusty's shed, humorously yelling "DIE, KRUSTY, DIE!" while doing so. However, the plane is mechanically unable to carry out Bob's kamikaze mission, and it merely bounces harmlessly off the shack's roof. The plane lands and stalls, and Bob is apprehended and subdued by Chief Wiggum. As Bob bemoans his failed plan (and how cliched the ending was), Bart is reunited with his family.
However, all is not well yet. Just as Bob is taken into custody, an Air Force operative accidentally drives a tank over the Wright Brothers plane, crushing it to bits (which is perhaps to be expected, as tanks aren't usually driven in the Air Force). After Bob gets hauled away back to jail, Grampa appears on his motorcycle, who tells everyone that he is going to "haul ass to Lollapalooza". This makes the Simpsons exclaim, "Here we go again" while Marge says it un-enthusiastically.
Behind the Laughter
A character resembling Rupert Murdoch appears in this episode as a prisoner, defending Fox from Sideshow Bob's critique. This was seen by some in the Fox Network as being somewhat insulting to the owner, and the writers were told that they should remove it just in case Murdoch was offended. When news of this potential appearance made its way to Murdoch himself, he said that he would love to be in this episode. Murdoch later appears in the episodes "Sunday, Cruddy Sunday" and "Judge Me Tender", where he voices himself. Dan Castellaneta voiced Murdoch in this episode.
Tom Baker Appearance
When the "Esteemed Representatives of Television" are called in, a character that looks remotely like Tom Baker in his famous Doctor Who outfit.