The Simpsons' twentieth season aired on Fox from September 28, 2008 to May 17, 2009. With this season, the show tied Gunsmoke as the longest running American primetime television series in terms of total number of seasons. The season was released on BD January 12, 2010, making this the first season released on BD. It was released on DVD in Region 1 on January 12, 2010, and in Region 4 on January 20, 2010. The season was only released on DVD in Region 2 in a few areas.
Once Ned and Homer's bounty hunting partnership takes a turn for the worse, Homer becomes the hunted, as Ned is on the prowl for him after he skips bail. Meanwhile, Marge mistakenly takes a job at an erotic bakery.
While trying to earn money at the country club, Bart acquires Denis Leary's cell phone after Leary angrily chucks it away. Bart keeps the phone and makes prank calls pretending to be Leary and when Marge finds out what Bart is doing she contacts Leary. Denis says Bart might as well keep the phone, but he advises her to activate the GPS system in the phone so she can track Bart's every move.
Bart meets his doppelganger, Simon Woosterfield, a member of the richest family in Springfield and the two decide to switch places. Simon adjusts nicely to his new digs at the Simpson home, while Bart discovers that his new siblings are plotting his death so they can have his inheritance.
In this years chilling trio of Halloween tales, Homer kills off celebrities so their likenesses can be exploited free-of-charge in How to Get Ahead in Dead-Vertising. Next, Transformer-like robots duke it out in Springfield in Untitled Robot Parody. And in Its the Grand Pumpkin, Milhouse, Lisa accompanies Milhouse to a pumpkin patch to await the appearance of the Grand Pumpkin. But when he finally appears, the Grand Pumpkin discovers people carving, disfiguring and eating his own kind, and he goes on a rampage of revenge.
A series of flashbacks depict Homer and Marge?s blissful courtship and their early married years.
Homer exploits Lisa's crossword puzzle talent to make money.
Homer suspects Bart's new friend, Bashir, of involvement with a terrorist plot to destroy the Springfield Mall.
Mr. Burns wins a professional basketball team in a poker game at the annual billionaire's retreat. In an effort to lure fans he decides to build a state-of-the-art facility, but the stadium site is on the last remaining bee colony in Springfield and Lisa leads the charge to block Burns' building.
Lisa meets an equally academic and creative new friend named Juliet (guest voice Emily Blunt).
Homer gets a glimpse of what his life would have been like if he had been elected class president.
Bart is informed that he and a select group of students have received perfect scores on a practice test for the upcoming Vice President's Assessment Test. As a result, he will be exempt from taking the real exam and will be transported by helicopter to a pizza party. Shocked at how Bart could have performed better than she did, Lisa freezes up when it comes time for her to take the exam. However, Bart and the others soon realize their trip is not what it seems, and their day turns into an adventure all its own. Meanwhile, when Homer is late on making an insurance payment, he must avoid bodily accidents at all costs until his insurance check is cashed, making for one very tense afternoon.
After too many years of financing their annual Mardi Gras party on home equity loans, Homer and Marge's adjustable-rate mortgage skyrockets and they are forced to put their house up for sale. Flanders does a good deed by outbidding Mr. Burns and purchasing the property, thus becoming Homer and Marge's new landlord. But when Homer publicly accuses Flanders of neglecting the Simpsons unsafe living conditions, Flanders threatens to throw the family out on the streets.
When Maggie disappears at a convent, Lisa goes undercover to solve the mystery.
The Simpson family travels to Ireland to take Grandpa to have one last beer at his beloved O'Flanagan's Pub in Dunkilderry. However, when they arrive, the little town of Dunkilderry isn't the quaint little Irish village that Grandpa remembers. It has become a gentrified yuppie enclave filled with hipsters on laptops and Bluetooths, surrounded by swanky stores and coffee shops. When they track down O'Flanagan's Pub, the bar is run down and nearly empty. After a few spirits, Homer and Grandpa buy the pub from Tom O'Flanagan (guest voice Meaney), and they are left with trying to bring the bar back to life amidst an ultra-hip, hardworking and sober Irish town. With a little help from Moe, they find the perfect scheme to bring the pub back to life and put the Simpsons on the map.
When Homer and Marge's marriage turns out to be invalid because Reverend Lovejoy was not licensed at the time, Homer asks Marge to marry him again. But when Homer mysteriously disappears on their wedding day, Bart and Lisa search for answers and are led on a cryptic trail of clues, leading them to Sideshow Bob (guest voice Grammer). Meanwhile, Homer finds himself chained to a pipe in a dark room. When a mysterious voice tells him that the key to unlock his chains is inside a lollipop, he frantically eats it only to discover the lollipop is made of fiery hot sauce and he is tormented as Bart and Lisa race to save him.
When Homer leaves Maggie on the doorstep of a convent to keep her safe as he rescues Santa's Little Helper from a sticky situation, the nuns at the convent take Maggie in. Lisa comes up with a plan to infiltrate the convent and rescue Maggie. After deciphering a series of cryptic messages at the convent, Lisa sets off to find Springfield's most coveted jewel and gets a little help from an ancient order of mystery buffs led by Comic Book Guy and Principal Skinner. But when Springfield's Freemasons, led by Mr. Burns, get wind of Lisa's quest, she must race to solve the mystery and find Maggie.
When Bart and Milhouse pull off a prank at Springfield Elementary, Milhouse takes the fall and gets suspended from school. Homer forces Bart to sign in under Homer's name and visit Grampa at his retirement home, and Bart soon becomes smitten with a delightful 11-year-old volunteer named Jenny (guest star Anne Hathaway). Hoping to impress Jenny, Bart offers to volunteer at the home. But as Bart and Jenny's relationship progresses, Milhouse emerges from his suspension and is less than thrilled about Bart turning his back on him for a girl. Meanwhile, Lisa does a report on what Springfield will look like in 50 years and becomes very depressed at the dreary outlook. A concerned Marge takes Lisa to a psychiatrist who diagnoses Lisa with Environment-Related Despair and puts on her on an antidepressant to cure her eco-blues.
When Homer observes Bart and Lisa struggling in certain aspects of their academic and social lives at school, he becomes a proponent of helicopter parenting, the process of closely monitoring a child and forcing them to succeed. Homer takes hovering to a new level when he chooses a nearly impossible subject for Bart's balsa wood model-building competition and gives Lisa some not-so-friendly advice on how to make friends. Meanwhile, Marge discovers a sauna in the Simpson family's basement that she finds hard to resist.
When Marge learns Springfield Elementary is the worst school in the state, she and Homer rent an apartment in the upscale Waverly Hills neighborhood so Bart and Lisa can attend a better school. When Lisa is ostracized by the popular girls at Waverly Hills, Bart uses his newly established bad boy image to impress the other students and increase Lisa's popularity by telling everyone she is best friends with the pop star Alaska Nebraska (guest voice Ellen Page). However, when Alaska Nebraska comes to town, Lisa is left wishing Bart had never opened his big mouth. Meanwhile, Homer moves into the new Waverly Hills apartment to make it look like someone is living there, and he quickly gets used to the bachelor lifestyle.
Marge and Lisa visit the nail salon where they engage in a spirited debate as to whether a woman can be smart, powerful and beautiful all at the same time. To prove their point, they spin four tales of famous women featuring famous Springfield faces: Selma as Queen Elizabeth I, Lisa as Snow White, Marge as Lady Macbeth and Maggie (guest voice Jodie Foster) as the idealistic architect protagonist from Ayn Rand's, The Fountainhead.
When nearby Ogdenville's economy crumbles due to tainted barley discovered in Krusty's veggie burgers, the unemployed workers of Ogdenville flock to Springfield. After Mayor Quimby closes Springfield's borders and enlists private citizens to help patrol them, Homer organizes a border patrol group.