Green Day is performing at Lake Springfield, where they fail to engage the audience in talking about the environment. They are killed when the pollution in the lake eats away at their vessel, causing it to sink. At the funeral,Granpa has a vision of a great catastrophe to come, but only Marge listens. Lisa and an Irish boy named Colin hold a seminar, which convinces the town to successfully clean up the lake. Meanwhile, Homer dares Bart to skateboard nude to Krusty Burger, but Bart is caught. Ned Flanders comforts Bart after being humiliated, but Homer ignores him, and adopts a pig. Homer keeps the pig's waste in an overflowing silo, which horrifies Marge, who tells Homer to dispose of it safely. While waiting in a line at the dump, Homer decides on a quicker means of disposal and dumps the silo into the lake, causing it to become heavily polluted. Nearby, Flanders and Bart bond during a hike and discover a mutated squirrel, which is captured by the EPA. Russ Cargill, head of the EPA, tells President that Springfield is extremely polluted and the government must take drastic action. As a result, the EPA places Springfield in a giant glass dome.

The police discover Homer's silo in the lake, and an angry mob approaches the Simpsons' home and torches it. The family escapes through a sinkhole which then devours the Simpson house. While on the run, Homer proposes that the entire family move to Alaska. Seeing the people of Springfield going insane, Russ Cargill manipulates the President into deciding to destroy the town. The Simpsons enjoy living in Alaska, but see an advertisement presented by Tom Hanks promoting a new Grand Canyon, to be located where Springfield is. Marge and the kids decide that they must save Springfield, but Homer refuses to help the town that tried to kill him. He goes to a bar and returns to discover that Marge and the kids abandoned him and left for Springfield. After a visit with a mysterious person, Homer has a vision and reaches an epiphany: he cannot survive without others and must save Springfield and his family. Meanwhile, Marge, Lisa, Maggie, and Bart are captured by Cargill and returned to Springfield. Cargill appears and tells the town Springfield is to be destroyed. A helicopter arrives and opens a hole at the top of the dome, lowering down a bomb. Homer climbs the dome and descends, knocking the escaping town people and bomb off the rope. Homer notices a motorcycle, grabs Bart, and cycles up the side of the dome. Bart throws the bomb through the hole, detonating it and shattering the dome. The town praises Homer, who rides off with Marge on the motorbike into the sunset. The film ends with everyone restoring Springfield, including the Simpsons' house, back to the way things were.

Lauren Adrian(J.Lo), an impassioned news reporter for the "Chicago Sentinel" wants to be assigned to the Iraq front-lines to cover the war. Instead, her editor assigns her to investigate a series of slayings involving young maquiladora factory women in a Mexican bordertown.

Worker Eva, originally from Oacaxa in the south, takes a bus to go back to her shanty-town home after work. After a while she is the last passenger still in the bus. The driver asks her if it is okay that he goes to a gas station to fill up, and Eva agrees. However, he takes her to a quiet place and assaults and rapes her together with another man, who then tries to strangle her. The two men, believing her dead, bury her alive. With the little energy she has left, Eva escapes.

Lauren heads to Mexico to investigate the murders, hoping that if she does well she'll be assigned to Iraq by Morgan. In Juárez, she meets up with Diaz(Banderas), her ex-boyfriend, who is the editor for the local newspaper "El Sol de Juárez." She also meets Eva.

The three try to find the two killers and have them prosecuted. For this purpose she starts working in the factory, in order to act as bait on the bus ride. Indeed the driver tries to assault her in the same way as Eva, and while police assistance was arranged they are at the wrong place. She manages to kill her attacker and escape. Later Diaz gets killed. Eva changes her mind and does not want to testify anymore against the second killer for fear of revenge, and tries to flee to the US, together with others in the trunk of a car. She gets caught and is sent back. Lauren convinces her to testify after all. For political reasons the Chicago Sentinel refuses to publish Lauren's story.