Marge decides it's finally time to separate from Homer, and quickly moves on with her life. Homer is initially devastated, but soon stumbles into a romance with a younger woman.
Patty and Selma try to quit smoking, but Patty moves in with the Simpsons when Selma takes it up again. Meanwhile, Maggie goes on an adventure with some local creatures.
The Simpsons are proud to be the most festively decorated house on the block. But when Lisa is traumatized at Krustyland Horror Night, she feels she cannot handle Halloween anymore.
Sideshow Bob finally kills Bart. Homerzilla rises when he doesn't get his daily doughnut. Bart, Lisa, and Milhouse fall into a cave filled with radioactive chemicals from the power plant.
Lisa makes a new friend at school - Harper, who happens to be super-rich, while Homer makes friends with Harper's dad and sets out to continue living the good life when Lisa decides to end the friendship.
Lisa tries to restore the reputation of a forgotten Springfield female inventor, while Bart takes full advantage of his parents belief that he is a sociopath.
A tale of Bart's journey from youth to adulthood, where he is constantly in search of approval from his father and in the shadow of his more-successful younger sister.
When Homer loses his job due to Marge's social media post, he begins working as a dishwasher at a Greek restaurant. Meanwhile, Lisa creates an app that can predict the effect any post on social media will have.
Bart and Principal Skinner battle over the affection of Bart's new teacher, and a new milk-based product that Homer buys from the Kwik-E-Mart causes big changes in Bart and Lisa.
Apu's nephew makes big changes when he takes over the Kwik-E-Mart business, and Bart decides that he's through with being bad after his latest prank spirals out of control.
Professor Frink's new invention turns him into a ladies' man, while a new pill at the Springfield Retirement Castle causes Grandpa to hallucinate back to his happiest moments.
Lisa tries to launch the career of a homeless Appalachian folk singer, but Bart warns her that she will just let her down. Meanwhile, Homer tries to rescue the cat, who is trapped in the walls of the house.
Lisa takes a job as veterinarian's assistant, but soon lets the responsibilities of the job get to her head. Meanwhile, Marge decides to take a job as a crime scene cleaner.
Lisa signs up for an opportunity to be part of a mission to colonize Mars in ten years, and Homer's strategy to use reverse psychology to talk her out of it backfires.
Homer tries to raise Smithers' spirits by finding him a man, and Lisa gets the lead in the school production of "Casablanca" alongside a new male student, sparking Millhouse's jealousy.
After Lisa overhears Marge say that she doesn't like Lisa's jazz music, Marge takes Lisa on a trip to Capitol City to regain her friendship. Meanwhile, Bart uses Maggie as his new partner in crime for his practical jokes.
After promising Marge the trip of a lifetime, Homer makes a deal with a travel agent to be a courier of a top-secret briefcase in exchange for a discounted family vacation to Paris.
