The president is induced by his adviser from the EPA to put a dome over Springfield to hold in the population and destroy the city.

Special features: Director commentary: David Silverman, Mike B. Anderson, Steven Dean Moore, Rich Moore; producers commentary: James L. Brooks, Matt Groening, Al Jean, Mike Scully, David Silverman, Dan Castellaneta, Yeardley Smith; deleted scenes: "Levels," "Springfield News," "DMV," "Sausage truck," "Emperor Moe," "Slightly alternate ending" ; special stuff: "Homer's monologue on the Tonight Show," "The Simpsons judge American Idol," "Homer introduces American Idol," "Lets all go to the lobby" ; a lot of trailers.