"Once Upon an Ed" is the 3rd episode of Season 3 and the 55th episode of Ed, Edd n Eddy. In this episode, the Eds end up stuck in Jonny's wall while Jonny and Plank are trying to read a bedtime story. The Eds then each try to explain how they ended up in their current predicament.
Jonny and Plank are about to slip under the covers and relax with their bedtime story, "Conrad the Lonely Stump." However, they get a surprise visit from the Eds as their faces burst out from a hole in the wall. Unable to free themselves, they ask Jonny for help, but he demands to know how they ended up inside his bedroom wall. Throughout the episode, each of the Eds tells the story about how they got stuck inside the wall, each one catering to their own imagination.
Eddy's story is a twisted personal fantasy version of the Cul-de-Sac with Eddy as the rich and popular king. As he walks down the street wearing his very fancy apparel, he bumps into Kevin, depicted as a monkey on a tricycle. Kevin greets Eddy happly with a "Hello, Mr. Eddy! Nice day for a walk isn't it, sir?". Eddy then tricks Kevin into crashing into a tree, after which Kevin calls himself a dork for falling for it. Eddy laughs before making a visit to his International Bank of Jawbreakers, Inc, where Ed and Edd work.
As Edd finishes a transaction with Rolf (shown as a noodle-limbed simpleton), Eddy comes through the entrance and greets his "fans", who all cheer for him. Jimmy is depicted in diapers with a massive and more complex retainer, Sarah has a giant mouth, and Nazz is in a bikini. Jimmy and Sarah compliment his suit and ask to touch it, but are slapped away with a glove. Edd greets Eddy cheerfully, only to be told to "get back to work, slacker", which he does without complaint. Eddy then plops himself on a throne and tells everyone via intercom that the bank's closed and they have to get lost.
With the other kids gone, the two Eds and Mr. Eddy head inside the bank's Jawbreaker vault, filled with jawbreakers from all over the world. Eddy sits on Ed's head, which starts stretching upwards like an elevator until he gets to the "Japan Flavor" Jawbreakers, which Eddy sucks upon greedily. Ed tries to lick another jawbreaker, but Eddy slaps him because they're not for employees. They are interrupted by Edd, who is flustered as he tries and fails to add up numbers on a calculator. Mr. Eddy then confidently states that he "made a mistake in the correlation between the gross revenues and the sum of the square root minus a piece of pie". Edd praises Eddy's genius, kissing his feet until the story transitions to the real world, where the real Edd chastises Eddy for his gross exaggeration of the truth, and begins telling a more realistic tale.
Edd's story is set in a world more accurate to the Cul-De-Sac's lane, though everything is drawn with blueprint-like measurements and numbers. Edd's story begins with a happy-go-lucky Jimmy with no retainer that arrives at Edd's "correctly designed jawbreaker bank". As the now retainer-less Jimmy tries to deposit a jawbreaker, Ed and Eddy are overly eager to grab it from him. As Eddy takes the duty seriously, he decides to put it in their jawbreaker vault, but Eddy ends up scaring away Jimmy by shoving Jimmy's jawbreaker (still in his hands) in his mouth. As Edd rants at Ed and Eddy for their constant selfish antics always ruining their schemes, Eddy takes over the narration, mocking Edd's voice and traits until the story is completely derailed and the scene goes back to reality. Jonny complains that their story stinks, to which Ed starts telling his story with a more dramatic opening.
Ed's story takes place in a dark-themed, monochrome world where only the characters and some objects are in color. The Kanker Sisters, deep inside the trailer park, devour a can of "Over-Radiated Mashed Potatoes" causing them to mutate and tear apart their trailer. At the same time, Edd is still berating the other Eds, but now he only speaks in incomprehensible "blah blah blah" and "yap yap" noises. They're interrupted by sudden tremors, followed by the other kids running from unseen danger. Jimmy trips and Sarah attempts to help him up, only for him to get crushed beneath the foot of Lee Kanker, who is now a hundred-foot-tall giant. The Eds attempt to hide inside a nearby house, but Marie Kanker fires an energy beam from a chicken growing out of her armpit at the house, causing it to turn into a giant bar of soap, to which Ed runs from in horror. They try to escape to another house, only for it to be turned into deoderent. The third house they try to escape to is destroyed by Lee Kanker, who wears it as a hat. The Eds then try to run away from the giant Kankers, but Lee starts literally blowing kisses at the Eds, slamming the ground with kiss-shaped craters around them to cut off their escape.. Eddy holds up a garbage can lid as a shield, but then the Kankers slam their heads together into a muli-eyed, big-mouthed monstrosity (to which Eddy replies "Ed, your story is getting weird!"), and blow a super-powerful kiss that blows the Eds away. As the giant Kankers close in on them, Ed triumphantly stands up, grabs his friends, and flies away into the air. The Kankers give chase with a flyswatter, eventually slapping Ed out of the sky, sending them crashing behind Jonny's house. Ed then discovers a small hole in the side of Jonny's house, declaring they found shelter, and promptly shoves Edd and Eddy inside along with himself, slipping in moments before the giant Kankers can grab them.
Ed then wraps up his story with, "And stuck in your wall we are. The End." Finished with their story, Eddy asks Jonny to pry them out of his wall, only to discover that he's already fast asleep. Eddy then sarcastically congratulates Ed for putting Jonny to sleep with his story, but then hear the sound of cracking as the Kankers appear in another hole in the opposite wall, having followed them inside. The Eds beg Jonny to wake up, but they are quickly dragged away one by one by the Kankers for "a little smoochin' time".
In Eddy's dream world, Jonny is not seen inside the Jawbreaker Bank. Strangely, he can be heard shouting 'encore' after Eddy's speech.
In Eddy's dream world, he says "You've obviously made a mistake in the correlation between the gross revenues and the sum of the square root, minus a piece of pie." Edd later quotes him as saying "the square root of a piece of pie." Although Eddy does mention "square root" in his statement, it was not worded as Edd said.
In Edd's dream world, Jimmy's jawbreaker is initially white. When Eddy talks to Jimmy, it is bright yellow. After Eddy offers to put it in the jawbreaker vault, it is white again. After Eddy puts it in his mouth and Jimmy runs away with it, it is yellow again.
In Ed's Dream World, the Kankers have 4 toes instead of 3 like everyone else.
When the Kankers first saw through Jonny's wall, Marie's shirt is gray, not black.
Jonny references several songs by The Beatles, as he mentions wanting to hear stories about octopuses' gardens, silver hammers, and Mr. Kite. All are well known Beatles songs ("Octopus's Garden", "Maxwell's Silver Hammer" and "Being for the Benefit of Mr. Kite" respectively).
"Conrad the Lonely Stump" reappears in "Tinker Ed," on the cover of the book that Sarah is reading to Jimmy. Interestingly, the brief dialogue she reads is about a tiny fairy princess, rather than a tree stump.
This episode may be based on the 1950 Japanese thriller Rashomon. In it, the main characters provide contradictory stories of the same event (a murder). As with this episode, it is never determined which one, if any, are correct. Owing to the movie, the Rashomon effect has since been coined to describe events in which witnesses give contradictory accounts.
After Jonny falls asleep, Eddy mocks Ed with the line "Way to go, Hemingway." Ernest Hemingway was an American author known for writing long-winded stories.
Kevin was depicted as a monkey before in "Look Into My Eds", when Eddy hypnotized him into being one.