On December 31, 1999, a costumed man warns Church about the dangers of Y2K. Church locks his friends up in a bomb shelter (basement) that evening. A nuclear holocaust occurs at the stroke of midnight, destorying much of Blood Gulch and mutating or injuring many of the surviving citizens. The gang are free from mutations.
When food runs out, the gang travel to Natick, Sea Massachussetts, in hopes that the Twinke" (splet "Twinkees" throughout the episode, due to copyright) factory survived. On the way, Lopez is exposed to nuclear waste and later mutates into a spider-like creature. Upon their arrival at Natick, they establish a town, dubbed New Blood Gulch, which Church mismanages into chaos. Octopus Lopez notices that he has put on some weight, and then begins to lay eggs.
Church is eventually kicked out of the town he founded, and his friends follow him, deciding where they should go next: a Carvel factory in Framingham, Sea Massachusetts. Meanwhile, Lopez's spawn hatch, and begin to kill the New Blood Gulch citizens.
The episode ends in a live-action parody of a famous episode of Dallas, where Pam Ewing wakes to find her husband Bobby in the shower. She tells him about the episode, which was apparently a dream. This is a parody of the famous Dallas shower scene, where an entire previous season of Dallas was revealed as a dream.