It is an unseasonably hot Easter at church, and no one is interested in Reverend Lovejoy's sermons. When the collection plate is passed round, Homer puts in a chocolate Easter bunny that he found in the dumpster, enraging Reverend Lovejoy, calling it a wicked idol, and provoking him to read the Bible from the beginning. The Simpsons all fall asleep.
Marge dreams that she and Homer are Adam and Eve. They peacefully live in the Garden of Eden until a snake (Snake Jailbird) tempts Adam into eating dozens of apples from the forbidden tree. He persuades Eve to try one when God (Ned Flanders) witnesses his sin. Even though Adam ate many apples, God only caught Eve eating an apple, and she is therefore banished from the Garden of Eden. Adam is unwilling to come clean, but misses Eve and thinks of a way of getting her back in by digging a tunnel with the help of some of the animals. God's unicorn, named Gary, becomes exhausted from the digging and dies just before God catches Adam trying to smuggle Eve back into the Garden. The death of the unicorn enrages him further, and he expels them both from the Garden of Eden.
Lisa imagines she and all the other Springfield Elementary students are Hebrews in ancient Egypt, with the Pharaoh (Principal Skinner) making them build a pyramid. Only Moses (Milhouse) can liberate the Hebrews. When Bart defaces the Pharaoh's sarcophagus, supposedly incited by the burning bush, he gets the other students punished. Lisa helps Milhouse produce plagues to scare the Pharaoh into freeing the Israelites; they fail. This in turn gets Lisa and Milhouse thrown in a Pyramid prison. When they escape, Milhouse gathers all the students and they attempt to leave. When they reach the sea, Lisa has an idea to get across: They simultaneously flush all the Egyptians' toilets to drain the sea. As they cross, the Pharaoh and his guards follow, but the water fills the sea back up and swallows them. They enjoy splashing each other, and then return to the shore. Pleased that they have escaped, Milhouse asks Lisa what the future holds for the Israelites, but Lisa disappoints Milhouse when she says that they have to wander the desert for forty years. Milhouse then asks if it is going to be smooth sailing for the Jews after that. Rather than disappoint Milhouse again with news of the ongoing anti-Semitism that will plague the Jews for many centuries, she distracts the crowd by sending them to search for manna.
Homer pictures himself as King Solomon. Lenny and Carl fight over ownership of a pie. King Solomon cuts it in half, sentences Lenny and Carl to death, and then eats the pie. King Solomon then presides over a civil case between Jesus and Checker Chariot.
Bart sees himself as King David, who kills Goliath, but has not won the war yet: Nelson is Goliath II, Goliath's son. Goliath II has killed Methuselah (Grampa), David's oldest friend. In retaliation, David challenges Goliath II, but having no stones to sling at him, David loses and is catapulted from the city. David then meets Ralph, a shepherd, who claims he can kill Goliath II. Ralph dies, which enrages David even more. He then trains to try to slay Goliath. Having to climb up the enormous Tower of Babel beforehand, David manages to kill Goliath by throwing a lit lantern down his throat. Goliath is surprisingly still alive, but is quickly killed by Ralph's gravestone, hurled by Ralph himself, who also had not died. Much to his shock, David is sent to jail as the townspeople claim that Goliath was the best King they ever had, building roads, libraries and hospitals. The dream ends with a title card that reads "A Bart Simpson Dream".
As the family wakes up, they find themselves alone in the church. Upon exiting they realize that the Apocalypse has come; fire rains from a red sky, and the Four Horsemen ride past. The Flanders ascend into Heaven, but The Simpsons do not; Lisa begins to ascend, but Homer grabs her ankle and pulls her back down. Instead, the Simpsons descend via a staircase into Hell, where Homer follows the delicious scent of barbecue. The episode ends with Homer screaming in agony (because there are no hot dogs, there is pineapple in the coleslaw, and German potato salad) as "Highway to Hell" by AC/DC plays over the credits.