Marge sends Lisa to a performing arts camp where she gets hooked on her new, hip lifestyle. Once back in Springfield, all Lisa can think about is returning.
Lisa invests in Nelson's brand-new business venture, but soon realizes that her friend's instant success might lure him away from the classroom. Worried that his judgment might be clouded, Lisa introduces Nelson to the well-educated and successful creator of Facebook, Mark Zuckerberg, only to find out that he too dropped out of school.
A visit by a Springfield Elementary alum-turned-Ivy-League student pushes Lisa to question her own go-getter attitude and reevaluate the scope of her extracurricular activities. Convinced that there is no such thing as having too many clubs or activities listed on her resume, Lisa jumps at the opportunity to coach Bart's little league team.
Beware of Ouija boards, vampires and unexpected guests in the 21st annual installment of the "Treehouse of Horror".
Discovering that Marge was once a stellar A+ student whose grades plummeted after being distracted, Lisa fears that she will end up just like her mom unless she pledges to focus solely on academics in an encore episode.
Following an unexpected turn of events, Bart finds Mr. Burns weak and vulnerable in the wilderness and secretly takes him into the Simpsons' home.
But when Homer and Marge learn about their new houseguest, they decide it's payback time, and Lisa, determined to stand up for Mr. Burns, learns that old habits die hard.
Bart helps nurse an injured pigeon back to health. After Santa's Little Helper eats the bird, Bart has a hard time coping with the loss.
It's beginning to look a lot like Christmas in Springfield, but while Marge gets in the holiday spirit, it's bah humbug for the rest of the family. Disappointed that she is alone spreading the holiday cheer, Marge sends a letter to Martha Clause to help her save the family Christmas.
Homer spends New Year's Eve in the Springfield Penitentiary after getting caught bribing an official. An FBI investigator offers to reduce his jail time if Homer agrees to go undercover as an informant to investigate Fat Tony.
After the fourth graders and fifth graders engage in a heated dodgeball battle, Bart discovers that one of the fifth graders has the same mysterious scar on his hand. Puzzled by the matching blemishes, Bart tries to understand why and how he got it, leading Marge to explain that seven years ago, she and her girlfriends formed the "The Cool Moms", a tight-knit group of moms who set playdates for their young boys.
When Smithers offers to help transform Moe's dingy pub into a more refined and trendy lounge, the revamped "Mo's" quickly becomes Springfield's local gay hangout.
Homer becomes obsessed with "Thicker than Waters", a 1980s family sitcom written by David Mamet, and models his parenting skills after the show's sensible father much to the chagrin on Bart, who desperately sets his sights on a brand new dirt bike.
Moe gets Homer to be his wingman, but becomes distraught when the women are drawn to Homer as well. Meanwhile, Marge discovers some gray hairs and tries a new more mature hair style to go along with it, much to Bart's dismay.
Bart's cartoon about an angry dad is turned into "Angry Dad: The Movie" and quickly becomes a critics favorite. When Russell Brand presents the Golden Globe to Bart's film, Homer usurps the podium and gives his own acceptance speech.
After a field trip to the desert, Lisa discovers that the desert water mysteriously makes typically combative creatures get along, so she brings some of the water home as a souvenir.
When Grampa moves in with the family after getting kicked out of the retirement home, Homer secretly tests the desert water on Grampa, who is instantly cured of his crankiness.
The town is abuzz when Cheech and Chong announce a Springfield stop on their much-anticipated reunion tour. But when Cheech and Chong take the stage in front of their loyal fans, the jokes were just not the same for Chong, so Homer steps in and delivers all the punchlines by heart.
When Homer inadvertently humiliates Bart in front of a stadium crowd, Marge encourages Homer to enroll in a fathering enrichment class taught by therapist Dr. Zander.
The family is greeted by folk singer Ewell Freestone when they visit a peach farm, but when Marge goes overboard with peach-inspired dishes, Lisa and Bart try to get rid of the unwanted fruit.
Fat Tony and Selma, Marge's painfully blunt sister, fall in love and get married after a whirlwind courtship. Marge has her reservations about the couple's marriage after Selma begins to prioritize her looks and ritzy new lifestyle over her family, so Fat Tony invites Homer and Marge to a weekend getaway at the Jersey Shore.
Homer become Springfield's most in-demand hair-stylist after discovering a talent for styling hair and opening his own salon. Unfortunately, Homer feels his talent is a curse when he has to listen to women's problems and gossip.
When the Simpsons discover a collection of keys to every door in Springfield, Lisa stumbles upon an eerie hidden classroom beneath Springfield Elementary School. When she shares her discovery with Principal Skinner, the secret room mysteriously disappears and he takes the only key away.
Feeling guilty for getting Mrs. Krabappel suspended after one of his school pranks, Bart helps her escape detention, and Ned Flanders winds up saving her life in the process.