When Homer’s mother returns to Springfield, she asks Homer for his forgiveness.

Moe torments drivers looking for a parking space at the Springfield Mall by picking a choice space, and telling people he’s not leaving. Meanwhile, inside the mall, Marge brings the kids to a store called “Itchy & Scratchy’s.” The kids mistakenly believe the store is devoted to their favorite cartoon characters. Instead, it sells itchy wool sweaters. Later the Simpsons make their way to a store called “Stuff-N-Hug.” There, Lisa builds her own stuffed dolphin. Bart, meanwhile, makes recordings of his voice saying nasty things about Homer. The recordings end up inside stuffed hippopotami. Homer grows furious when the stuffed animals insult him. He starts ripping the hippos apart. When the Simpsons return home, they realize someone is inside the house. Fearing it’s a burglar, Homer grabs hold of “The Defender,” a crude defensive weapon made of a cinderblock and chain. Moments later Homer finds his mother, Mona, baking an apple pie in the kitchen. Homer drops his weapon. The last time the family saw Mona she was hiding from the government (she’s still wanted for unlawful things she did while supporting 1960s radical causes). Mona says she’s through with protests. Now she wants to devote herself to the most important thing in her life: Homer. Remembering how his mother broke his heart in the past, Homer is reluctant to believe that Mona won’t hurt him again. That night Homer watches the ESPY Awards, hosted by Lance Armstrong and Fozzy Bear. Mona interrupts the show, and tucks Homer into bed. She asks Homer for his forgiveness, and then leaves. That night Homer tosses and turns in bed. He feels guilty for rejecting his own mother. He decides to make her a card. When he makes his way to the living room to give it to her, Homer discovers that his mother has passed away.

At the Springfield Funeral Home, Homer and Grampa collect Mona’s ashes. When Homer returns home, he mopes around in bed. Marge and the kids try to cheer him up. Later Homer makes his way to Moe’s tavern. There he tells the barflies he wishes he could have told his mother he loved her one more time. Moe pulls out a Ouija board, but ends up contacting a former business partner in the great beyond. Later Homer discusses the hereafter with Apu and Flanders at the Kwik-E-Mart. When Homer returns home, Marge finds a “video will” among Mona’s belongings. In her will Mona leaves Bart a Swiss Army knife; Marge gets a purse made of hemp; and Homer receives a difficult task: at 3:00, he’s to climb to the highest point at Springfield Monument Park to dump her ashes. Homer and his family make their way to the park, where Homer climbs to the top of the butte. At exactly 3:00, Homer dumps his mother’s ashes into the air. A gust of wind carries them into a nearby crater, destroying a missile’s guidance system. Homer realizes his mother tricked him into participating in one last “hippie protest.” Soldiers guarding the missile fire at Homer, who trips and ends up landing on top of the missile. Homer slides down the side of the missile, and is eventually overpowered by guards.

It turns out the missile belongs to Mr. Burns, who stands to benefit from a war between Sweden and Norway. It’s his intention to fire the missile at Uruguay. A short time later Bart tosses Homer the Swiss Army knife that Mona gave him. Homer makes a new “Defender” using a chain and cinderblock. Marge burns her hemp purse near an air conditioning duct leading to the missile crater. The fumes intoxicate the soldiers. Homer advances with his “Defender,” overpowering guards. A huge fireball erupts from the crater, and Homer descends from the sky in a parachute. Lisa tells her father that Mona’s spirit will live forever thanks to his bravery.