"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 - inside their wall. Throughout the episode, each of the Eds tells the story about how they got stuck inside the wall.
Eddy's story is a twisted reality/fantasy of how the Cul-de-Sac would be if he was the King. As he walks down the street wearing his very fancy apparel, he bumps into Kevin. Kevin, seen as a monkey who rides a tricycle, is nice to Eddy. Kevin then asks Mr. Eddy "Nice day for a walk isn't it, sir?". "Mr. Eddy" then tricks Kevin to crash into a tree (with Kevin calling himself a dork for that) before making a visit to his International Bank of Jawbreakers, Inc, where Ed and Edd work. As Edd finishes with the now slim-headed simpleton Rolf, Eddy comes through the entrance and greets his fans. The fans then begins cheering for Eddy. The fans are shown in the forms of: Jimmy in diapers with an even bigger retainer made of tools, Sarah that's even more loudmouthed than ever and Nazz in a bikini. Jimmy and Sarah then approach Eddy with the former asking if he is wearing a new suit. Sarah then asks if she can touch it, but Mr. Eddy slaps both Sarah and Jimmy away with his glove. Edd says good day to Mr. Eddy and asks how was his day, but Mr. Eddy tells him to get back to work. Eddy then heads to his throne chair and announces to everyone to drop their jawbreakers as the bank is now closed, so the customers then leave. The two Eds and Mr. Eddy then go to investigate the jawbreaker vault, which Ed's head is the key to. Inside, there are Jawbreakers from all around the world. As Mr. Eddy takes the Ed-elevator up to the Japanese jawbreakers, Edd deals with the inventory. Mr. Eddy takes a Japan-flavored jawbreaker and proceeds to eat it. Ed then licks some of the other jawbreakers when Mr. Eddy tells him to not touch those, since he is an employee. They are interrupted by Edd, who claims that no matter how many times he goes over the numbers, they don't add up. Mr. Eddy swoops in and fixes it, by explaining 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 then wonders what he was thinking and kisses up to Eddy. In reality, Edd questions Eddy "The square root of a piece of pie?" Edd stops the story because it sounds way too fictional to be true and decides that he should continue the story.
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 is to deposit a jawbreaker, Ed and Eddy are eager to take care of it. As Eddy takes the duty seriously, he decides to put it in their jawbreaker vault. But Eddy's mouth doesn't count as a jawbreaker vault, so Jimmy runs off. As Edd releases his anger over the failure on Ed and Eddy, Eddy interferes and begins mocking Edd's appearance and traits while doing so. Jonny points out that Edd's story is boring. Ed then states a story that appears to pick up where Edd's story left off.
Ed's story is just as believable as Eddy's. The Kanker Sisters, deep inside the trailer park, slowly devour over-radiated mashed potatoes and then undergo a mutation tearing apart their trailer. At the same time, Edd is talking in blahs and yaps (Ed understands Edd's talking as this), as the Kanker Sisters return as giants. After witnessing the sight of the giantesses, and after watching Jimmy get stepped on and crushed under Lee Kanker's giant, stinky barefoot, the brave Eds try to make it inside a house, but a chicken armpit laser from Marie turns the house into soap, forcing the Eds to run away. The chicken from inside Marie's armpits then shoots a beam at another house, turning it into some deodorant, forcing the Eds to run away. The Eds then discover the third of the Kanker Sisters when trying to hide in a yet another house. The Eds then try to run away from the giant Kankers, but Lee blows kisses at the ground to stop the Eds from going anywhere. Eddy protects them with a garbage can lid, but then the Kankers put their heads together (literally, Eddy even notes to Ed that his story is getting weird) and blow a powerful kiss that really blows the Eds away. As they begin coming closer, Ed flies away with his friends. He is eventually hit by a fly swatter used by Lee and he and his friends plummet down to earth. He finds shelter and pushes Edd and Eddy into a mouse hole in Jonny's house. He then pushes himself into the mouse hole just as Lee is about to grab him.
Ed then wraps up his story while saying, "And stuck in your wall we are. The End." The Eds have now told Jonny his story, so now it is time for Jonny to let them down... but he is already fast asleep. Eddy then sarcastically congratulates Ed as it was his story that put Jonny to sleep. Mystical sounds appear and a hole in the opposite wall reveals the Kanker Sisters. A quick look at Jonny and they're gone. The Eds then one by one get dragged into the wall for a little "smoochin" time". In the Eds' words, "it's a never ending story".
Jonny: [after knocking his wall and getting a response] "Did you hear that, Plank? We got wall weasels!"
Edd: "Well, let's see now. The story begins..." Eddy: [annoyed because Ed is drooling on his head] "Oh come on! Ed's drooling on my head!" Edd: [off-screen] "There's an art to storytelling, Eddy. One must use a palette of words to make images, blend sentences and project them in an interesting way." Ed: "Boring!" Jonny: "Yeah, boring!" Eddy: [smugly] "See? Jonny's got your number, Double D."
Edd: "Agony, agony! As many times I've gone over these numbers, they don't add up!" Eddy: "You obviously made a mistake in the correlation between the gross revenues and the sum of the square root. Minus a piece of pie." Edd: "Oh, what was I thinking? You're a genius, Mr. Eddy!" [starts kissing Eddy's feet in Eddy's story] [Transition back to the Eds on Jonny's wall] Edd: [disappointed with Eddy's story] "The square root of a piece of pie?!" Eddy: "What?" Edd: "Pure fiction, Eddy! Your story can only be described as cockamamie!" Ed: "Tsk tsk tsk. I have never heard such language."
Edd: "Take note, as I am a..." Eddy: [interrupts Edd and saying mocking things while Edd's (inside the story) look changes] "...stupid Sockhead! And a babbling dweeb who can't lift a butterfly!" [transition rips back to the Eds in the wall] Eddy: "I wish I was just good looking as Eddy!" Jonny: "Boy, this story stinks. Plank and I want real stories with stuff like octopus's gardens, silver hammers and Mr. Kite!" Eddy: "Open a window, Jonny, and get some air." Ed: [telling his story] "And so it went! Little did Ed, Edd, and Eddy know that deep within the intestines of the trailer park, the Kanker Sisters were planning to foil the brave Eds' attempts with over-radiated mashed potatoes. Slowly, one-by-one, they would devour the tainted spuds!"
Eddy: [after the Kankers join heads] "Ed, your story's getting weird."
In the first scene which has the Kankers in Jonny's wall, Marie's shirt is gray, not black.
Eddy says "minus a piece of pie" in his dream world, but Edd later quotes him saying "the square root of a piece of pie."
In Eddy's dream world, Jonny is not seen inside the Jawbreaker Bank, however he is heard shouting 'encore' after Eddy's speech.
Throughout most of Edd's story, Jimmy's jawbreaker is white. When Eddy tries to take it, it is bright yellow for some reason, but in the next shot, it is white again. Then, when 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.
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" receptively).