Patty and Selma invite themselves over to stay in the Simpson home without asking, much to the anger of Homer. The twins light up cigarettes, causing Bart and Maggie to cough severely. Homer makes a deal: if they smoke at all during their uninvited stay, Patty and Selma must leave right away. Homer installs smoke alarms all over the house to ensure this. The twins go into a downstairs bathroom to smoke, seeing as Homer forgot to put a smoke alarm there, but they catch fire from the tap water. Lisa informs Marge that this is possibly a result of fracking, which she discovers that Mr. Burns is operating. She successfully calls on Democratic Assemblywoman Maxine Lombard to stop the fracking.
Burns is furious at Lombard and storms into her office, but the two end up having sexual intercourse and vow to continue their romance despite their political differences. On learning that he must obtain the mineral rights to all land in Springfield in order to resume his fracking operation, Burns gives Homer the job of marketing it to the citizens of Springfield. At a Town Hall meeting, Professor Frink warns about water contamination, but Homer promises $5,000 to every person who gives their mineral rights to Burns. When he is about to resume the operation, Burns discovers that Marge did not give permission to him, and thus the project is abandoned, infuriating many residents who were looking forward to the money. Knowing that he will lose his new job, Homer is angry at Marge, and Burns breaks up with Lombard.
Lombard takes revenge on Burns, demolishing his mansion to use the land for various liberal causes, including Robert Siegel's National Public Radio. Burns plans an even bigger vengeance, and resumes his hydraulic fracturing at maximum power, causing earthquakes in the city. Marge pleas with Homer to shut it down, and he lights the inflammable water to burn the fracking plant down. On seeing that Homer and Marge can reconcile despite their differences due to their passion, Burns and Lombard get back together.
During the credits, Burns and Lombard are seen having a conversation while lying in bed with their tablet computers.