"Life’s A Glitch, Then You Die" :On December 31,1999, as the New Year’s ball descends, it becomes apparent that Homer, the power plant’s Y2K compliance officer, failed to debug the company’s computer system. As a result, the plant’s faulty computers corrupt other systems throughout the world, creating havoc with electronic devices everywhere. Even Krusty’s pacemaker is not immune, and Bart rushes to his side when he collapses. The boy discovers an envelope in the clown’s hand. Lisa reads the contents of the document within and realizes that the government plans to evacuate the Earth via spaceship.

The family makes its way to the ship, but a guard announces that Lisa may take only one parent with her on the journey. Lisa quickly chooses Marge. Homer and Bart race to another spaceship nearby. But they grow weary when they realize their fellow passengers include Dan Quayle and Tom Arnold. The pair realize the ship is not headed for the safety of Mars, but is being piloted into the sun.

"Desperately Xeeking Xena": On Halloween night, costumed children line up in the school gymnasium where Chief Wiggum uses an x-ray machine for candy inspection. Milhouse shoves a pillowcase full of candy into the device, causing it to explode. The accident imbues Lisa with super strength and Bart with the ability to stretch like rubber.

Now Clobber Girl and Stretch Dude, the pair realize they can use their abilities to fight crime. Meanwhile, a super-villain who calls himself "The Collector" (who is, in actuality, the Comic Book Guy) kidnaps actor Lucy Lawless and seals her in a protective Mylar pouch. Bart and Lisa penetrate The Collector’s lair and announce that his collecting days are now over. But the Comic Book Guy overpowers the pair and slowly lowers them into a vat of boiling Lucite.

Moments later, Lawless flirts with the Collector, and when his guard drops, she attacks him. Staggering backward, he plummets into the boiling Lucite. Lawless then saves Bart and Lisa.

"I Know What You Diddily-Iddly-Did": As the Simpsons drive home from a whale watching expedition, Marge accidentally runs over Ned Flanders. Homer successfully makes it seem as if Flanders suffered a heart attack. When the family returns home from Flanders’ memorial service, they observe that someone wrote "I Know What You Did" in red letters on the front door. The family realizes that someone is trying to scare them into confessing.

When Homer admits that he left evidence on Flanders’ corpse that ties the family to the crime, it is decided that the body must be exhumed. But when the coffin lid is opened, Flanders, still very much alive, thanks everyone for rescuing him. Marge responds by smashing Flanders in the face with a shovel, killing him. The family retrieves the incriminating evidence and reburies the body.

But when the Simpsons return home, they realize they someone wrote "I Know What You Did" all over the walls. The family takes refuge at a deserted roller skating rink. There, a raincoat-clad figure terrorizes the family. One by one, family members disappear until only Marge remains. The figure emerges from the shadows, revealing himself to be Grampa. He chastises everyone for going whale watching without him on his birthday.

Later, the family is arrested and beheaded by a giant guillotine.