Kristen Wiig (“Despicable Me 2”) guest-voices in the season premiere episode as an intense, high-strung FBI agent whom Lisa enlists for help when she suspects that something sinister has happened to Homer.
Also, Elizabeth Moss (“Mad Men”) plays a grateful mom who names her baby Homer Jr., after Homer Sr. helps in the delivery of the child.
The opener of the 24th annual “Treehouse of Horror” is from Guillermo del Toro and features monsters and classic characters from horror films throughout history.
In the first of three spine-tingling stories, Homer rides around Springfield wreaking havoc in a rhyming take on a popular children’s tale.
In “Dead and Shoulders,” Bart is beheaded during a kite accident, his head is attached to Lisa’s body and they must live together as one.
The final terrifying tale, “Freaks no Geeks,” features Mr. Burns’ traveling circus, The Burnsum and Bailey Circus, which has stopped in Springfieldland in the 1930s. Trapeze artist Marge and Strong Man Homer are performers and things go awry when circus freak Moe starts to make advances towards Marge
Four Springfielders are prompted to try to right past regrets following the funeral of a beloved neighbor. Homer regrets selling his Apple stock to buy a bowling ball, Marge worries she caused Bart’s rebellious streak, Mr. Burns reminisces about a romance he gave up with a beautiful Parisian woman and Kent Brockman admits he was too afraid to leave local news and follow his former partner Rachel Maddow to cable news.
Marge encourages Homer to embrace his “You-Only-Live-Once” spirit by inviting an old pen pal to stay with him and cross items off of his “to-do” list from when he was a 10-year old.
Meanwhile, Lisa institutes a new honor code at Springfield Elementary
Songs: Denisa Donatelli -- "You Only Live Twice" Parody
Homer remembers his Lamaze skills when he’s forced to deliver a baby in an elevator. When the mother (guest voice Elizabeth Moss) names the child Homer Jr., he quickly develops a deep emotional bond with the kid.
Meanwhile, Lisa is recruited by the cheerleaders of the local pro football team, the Springfield Atoms
Lisa finally makes a new best friend, Isabel Gutierrez, only to discover that she’s a Republican and her opponent in the campaign for second grade class representative
Principal Skinner promises the students that the best-behaved among them can take a ride in a submarine. When Skinner gives all the kids a clean slate, Bart believes even his own past indiscretions will be forgotten if he doesn’t get into any more trouble.
Meanwhile Lisa tries to help a cash-poor Krusty to turn things around by suggesting he sell the foreign rights to his shows
Springfield is inundated with holiday revelers after the nuclear power plant springs a radiation leak, causing snow to fall all over town.
When the tourists drive up Christmas shopping prices, Marge opens up the Simpsons’ house to boarders