Mona Leaves Us Mr Burns concocts another evil plan to get rid of Mona and Bart misbehaves on the bus because a gremlin is attacking again so Skinner has him sat next to Uter who offers him German sweets.
Mr Burns is bored watching the security cameras.
"Sir, what's wrong?" Smithers asked.
"Oh Smithers. Things are just not the same without that oaf Simpson to torment and put down with insults about how he'll never amount to anything..." said Mr Burns. "I just haven't been the same since he left. Nothing could make me happy more than taking everything from him and watching him forced to work for me everyday..."
"What about that time you crippled that Irish man when you were just a boy?" Smithers asked.
Mr Burns laughed hysterically. "Oh that crippled Irish man! Oh!" He had a flashback of himself as a young boy driving dodgems. He rammed into an Irish man who was painting the fence of the dodgem arena.
"Why you!" The Irish man was about to yell at him but suddenly realised who he was about to yell at. "Ah! Master Burns! Eh feel free to keep smashing into me! There's a good lad!"
Young Burns did so while giggling.
"Ow! Ah! Oh lord have mercy! Oh me Jesus!" the Irish worker cried as young Burns rammed and smashed him with his dodgem car.
In the present Mr Burns continued laughing constantly while doing things such as writing documents, having a bath and even sleeping.
Eventually he stopped while having breakfast.
"Oh Smithers, what was I laughing at?" Oh! No I remember, that crippled Irish fellow! Ohohohoho!" Mr Burns asked before remembering what he found funny and laughed even more.
Smithers sighed as he served Mr Burns some tea.
Meanwhile at Springfield elementary school Milhouse has a space lunch with a puzzle on it. The answer is that the glyphs are numbers drawn at a mirror so they are mirrored on a line of symmetry.
"Found it!" said Martin.
"Done! said Bart.
"Easy!" said Milhouse.
"How did I do?" said Nelson.
"Excellent Nelson!" said Martin.
However Lisa was stumped by the puzzle. She couldn't find the answer because she was over thinking it.
Elsewhere Homer was being a hippy again on the farm. After some begging his mom and Seth and Munchy went with him in her friends hippy wagon on a freak out.
However his freak out stopped at the school.
Bart was embarrassed to see his dad get out and enter the school to bring merriment.
"Please! Not in here!" Bart buried his head in his arms. However Homer came in wearing a jester hat and yelling in a megaphone about bringing down the establishment and giving everyone bead necklaces.
Marge was not happy with Homer for going on another one of his freak outs.
That evening Grampa was having his hair cut. However he kept being fussy and wanted a haircut like Humphrey Bogart.
Lisa came in while pondering Milhouse's lunch box puzzle.
"Grampa am I growing dumb?" Lisa asked.
"I'm afraid so sweetie, it's the Simpsons gene you see, it affects all Simpson kids. I'll prove it!" said Grampa after Marge left to have a break away from Abe's nagging and request for impossible haircuts.
Grampa took Lisa up to the attic and showed her old report cards.
"Your Dad used to be as smart as a monkey. Then the Simpsons gene kicked in..." said Grampa.
Homer's grades got worse and worse.
"Then there's your brother's! His too were promising until the Simpson gene took hold..." Grampa explained.
Bart's grades got worse as the smiley faces on them from his teachers turned into angry faces then skulls.
"Wait! Just cos that happened to Dad and Bart doesn't mean it will happen to me!" said Lisa. "Will it?"
"Sure! But doesn't mean you can't live a long and pointless life!" said Grampa before carelessly shutting her in the attic. Yes he shut her in the attic...
Lisa looked around nervously as the attic was dark and she could hear Hugo breathing. He was glaring at her.
"Abe! Did you lock Lisa up in the attic?!" Marge scolded him.
"D'oh! I thought she was the kid you have to keep locked up! You know the screwy one!" said Abe.
"Abe, that was Hugo, Bart's brother! And we're not allowed to do that anymore because we got reported to social services! And besides our accuser is right! It's cruel!" said Marge as she let a frightened Lisa out of the attic. She was traumatised.
Lisa then started explaining Grampa's spiel about the Simpsons gene.
"The Simpsons gene?! That old bungus?!" said Mona. "Abe, Homer's grades slipped because he got a crayon stuck up his nose! Bart's are because he deliberately acts up in class! He's actually rather smart when he wants to be!"
"And I'm sure Mona lived a long and successful life!" said Marge.
"Well, until I was on the run I had aspirations of being a teacher!" said Mona.
"Oh that's lovely Mona!" said Marge.
"Yeah Grandma!" said Lisa.
Suddenly Lisa found the answer to Milhouse's puzzle.
"Eureka! They're all numbers from one to seven but are reflected in a mirror! The next is eight!" said Lisa.
"Uh, even Ralph solved it before you Lis..." Bart tried to discourage her but it didn't work.
Mr Burns set up the perfect trap. A book signing on her memoirs.
She attended it and signed with an alias.
"Mona Simpson. Forging an official document is a felony." said Mr Burns smugly as she was arrested.
Homer cried as she was taken away.
"Don't worry Homer. I won't let her get taken away!" said Oscar.
As the police truck took Mona and several female prisoners to jail Oscar caught up on a motorbike wearing leather and black sunglasses.
"Uh Eddie is that a kid riding a motorcycle?" said Lou.
Oscar threw a tear gas canister into the driver's cabin forcing Eddie and Lou to bail. He got in wearing a gas mask and drove the police truck elsewhere.
Mona was happy with Oscar's rescue.
"Are you always this dashing and daring?" she asked.
"Uh... Bart's probably already mentioned this but whether I'm helping him get his own way or correcting some injustice I'm a little hot headed and uh tend to shoot my way out of situations..." said Oscar.
"Oh dear..." said Mona. She really didn't want him having to go on the run as well.
"Oscar, just bail. I'll get us girls to freedom." said Mona.
"No can do lady. I promised Homer I'll get you free and safe. And that's what I intend to do. I'm taking you to England." said Oscar.
At home Homer was upset his mother had been taken from him again.
At school Bart was on a school trip on the bus but he saw a gremlin on the side of the bus again.
"Milhouse! Look out the window!" Bart begged him.
"Nuh uh! If I do that I subject myself to wedgies, wet willies or the dreaded rear admiral!" said Milhouse.
Bart anxiously watched the gremlin tear apart the bus. He had to stop it.
He disturbed Otto.
"You see the gremlin right Otto?" Bart asked.
"Oh sure, I see him!" said Otto. He rammed into an AMC Gremlin driven by Hans Moleman.
"Oh dear!" said Moleman he crashed into a tree and caught light.
Bart saw that the gremlin avoided being smooshed by hiding in the wheel cavity. It made a throat cut gesture at him.
"Everybody there's a monster on the side of the bus!" said Bart.
Everyone screamed and looked out the window.
The gremlin had hidden somewhere.
"There's no monster!" said Nelson.
"You're deceptive!" said Ralph.
"Bart stop scaring your classmates and sit down!!" said Krabappel.
Bart started creeping Milhouse out by asking if he believed him. "You believe me right? Dear, sweet Milhouse?"
"Uh, you're kinda creeping me out! I'm really gonna sit uh next to that foreign exchange student!" said Milhouse. He sat next to Uter.
"Ah Guten tag! May I offer you a bite of my Candy bar? I also have a bag of Almond Joy Joys!" said Uter offering sweets, including Joy Joys with iodine!
However Bart was going on about the gremlin again and scaring everyone.
"That's it Simpson! Go and sit next Uter! Milhouse return to your usual seat." Skinner yelled.
Bart was sat next to Uter and his hands were tied so he couldn't move. Uter offered him a lick of a candy cane he had been sucking. Bart reluctantly licked it and grimaced in disgust.
"So Uter, now we're friends, how about untying me?" said Bart.
"Oh sure!" said Uter untying him.
However Otto saw too late as a police bus pulled out and crashed into it.
The lady convicts all broke out and escaped. Including Mona and Oscar.
Bart surveyed the damage to find a dead gremlin crushed by the impact. He showed it to everyone.
"Um, I guess we owe you an apology Simpson." said Skinner.
"Damn right you do..." said Bart.
Homer was still upset over his mom when he got a phone call. It was Oscar.
"I'm calling from Heathrow. Mona's safe in England. I'll be looking after her for a while until things cool off over there." said Oscar.
"I don't know, this phone call better not cost me..." said Homer.
"Homer..." Oscar sighed.
Mona was put on. "I can't stand to be apart from you son! But I will return someday." said Mona.
"Oh and Homer, when she does. Don't blame her for leaving you again. It's not her fault. It's-" Oscar explained.
"Yeah I know, it's old man Burns! Well I've had enough! I'm not working for him anymore so I don't care what he says or does. It's payback time!" said Homer.
"That's the spirit Homer." said Mona.
They then put the phone down.
However Mr Burns angry Mona escaped yet again turns his attention to Seth and Munchy's allotment. He hires goons to burn the allotment.
They begin smashing up and burning things. However Homer arrives with a little help. A parade of Globex helicopters!
"Simpson!" Mr Burns growls.
Hank Scorpio instructs his goons to fight and kill Mr Burns' goons. They soon eliminate all of them.
"You'll pay for this Simpson! I swear! You'll rue this day!" Mr Burns rants.
"Take a hike old man!!" yelled Homer.
Seth and Munchy didn't know what to say.
"Uh..." said Seth.