Morpho sends Sonic to a dimension where he never existed. Sonic must unite his gang and help take back the alternate dimension village.
- Badnik (alternate dimension) (Sonic Boom) (First appearance)
- Scorpion Bot (alternate dimension) (multiple) (First appearance)
- Beaver Policeman (alternate dimension) (First appearance)
- Beth the Shrew
- Comedy Chimp (alternate dimension) (Mentioned)
- Dave the Intern
- Dave the Intern (alternate dimension) (First appearance)
- Dr. Eggman
- Fennec Male
- Lady Goat
- Lady Goat (alternate dimension) (First appearance)
- Lady Walrus (alternate dimension) (First appearance)
- Lord Eggman (First appearance)
- Metal Sonic (Cameo)
- Mike the Ox
- Old Monkey
- Rabbit Girl
- Rabbit Girl (alternate dimension) (First appearance)
- Rebellion (First appearance)
- Fennec Male (alternate dimension) (First appearance)
- Gogobas (alternate dimension) (First appearance)
- Mike the Ox (alternate dimension) (First appearance)
- Team Sonic (alternate dimension) (First appearance)
- Amy Rose (alternate dimension) (Sonic Boom) (First appearance)
- Knuckles the Echidna (alternate dimension) (Sonic Boom) (First appearance)
- Miles "Tails" Prower (alternate dimension) (Sonic Boom) (First appearance)
- Sticks the Badger (alternate dimension)
- Wild Cat (alternate dimension) (First appearance)
- Wolfie (alternate dimension) (First appearance)
- Reindeer Girl
- Shadow the Hedgehog (Cameo)
- Stratford (alternate dimension) (First appearance)
- Team Sonic
- Vector the Crocodile (Cameo)
- Wolf Policeman (alternate dimension) (First appearance)
- Wild Cat
- Sonic Boom World
- Sonic Boom World (alternate dimension) (First appearance)
- Lord Eggman's Lair (First appearance)
- Seaside Island (alternate dimension) (First appearance)
- Eggmobile (alternate dimension) (Sonic Boom) (First appearance)
- Knuckles' monster truck
- Sonic Speedster
On Seaside Island, Dr. Eggman has arrived to visit Mombot, who is living outside of Hedgehog Village, and has brought a chocolate bobka for her. When Mombot meets Eggman at the door though, she tells him that he is late and instructs him to place his bobka next to the one his "brother" Morpho has brought, prompting Eggman to remind her of Morpho's true origins. Inside the house, Eggman meets Moprho at the table, and the two talk about how Eggman has been trying to destroy Sonic and his gang, during which Morpho brings up that getting rid of Sonic would make Team Sonic fall apart, thus making them easy picking for the duo. However, the two begin fighting when Eggman starts making fun of Morpho by using his "Steve Eggman" alias, until a dissatisfied Mombot breaks them up. She then tells them to get out and work together to destroy Sonic, to which Eggman and Morpho agree to.
Later, Sonic and Knuckles, both in their customized racecars, are racing each other through the canyons. Before Sonic can reach the finish line however, a portal opens up in front him. Unable to stop his car in time, Sonic slides into the portal and disappears while Knuckles crosses the finish line, completely occupied over the fact that he won the race. Meanwhile, Eggman and Morpho, the latter of whom opened the portal Sonic passed through with a box-shaped device, have been watching everything from the cliffs. As Morpho mentions that he has sent Sonic to another dimension, Eggman (who recalls a similar occurrence) expresses his worries about the universe-destroying abnormality that occurs when two of the same person occupies the same dimension. Morpho assures him it will not be a problem though, as he has sent Sonic to a dimension where no other Sonic exists, and the two villains laugh in glee over their success.
Somewhere else, Sonic and his car emerge from the portal and comes to a halt in what looks like the Village Center. Sonic thinks he just got through a shortcut, and looks around. After Sonic sees a billboard of Knuckles and a TV commercial in a local shop where Knuckles is advertising Knuckles' Upper-Body-Only Workout Center however, he starts to get confused. Back in the Sonic Boom World, Eggman and Morpho have arrived at Amy's House to start the next phase of their plan: have Morpho take Sonic's place so no one will notice his absence. Morpho promptly disguises himself as Sonic, and tries charming Amy into coming along with him on a trip. Amy, however, does not buy the sweet-talk. Realizing it is Morpho, Amy points out more flaws in Morpho's acting when he tries to defend himself, and shuts him out, much to Eggman's frustration.
In the other dimension, Sonic finds the native Amy and tries to greet her, only for Amy to get defensive. As Sonic asks what is wrong, he notices Lord Eggman arriving on a throne carried by Gogobas, which prompts Amy to hide. Recognizing Sonic as a newcomer, Lord Eggman demands he kneels before him, only for Sonic, who thinks he is his Eggman, to snark back at back him, much to the onlookers' shock. Sonic gets ready to fight the agitated Lord Eggman, only for the police to take him to jail. In jail, Sonic realizes he is another dimension and tries to explain himself. In his cell, Sonic meets the alternate Dave, who is in jail for forgetting to give Lord Eggman extra pickles at his workplace, Gourmet Burger. As they two talk, Amy breaks down the cell wall and explains that she has "come to rescue the hedgehog who stood up to Lord Eggman". She also allows Dave to come along as thanks for his exemplary customer service, and the two prisoners escape.
During the evening, Sonic and Amy arrive in Gogoba Village, where Amy introduces him to the Rebellion, a small group opposing Lord Eggman's rule. There, Amy brings Sonic before the Rebellion's leader, who is an alternate Sticks, much to Sonic's surprise. Sticks offers Sonic's a place in their Anti-Eggman unit, which Sonic accepts. However, he insists that they need the full team to defeat Lord Eggman, which leaves him with just the native Knuckles and Tails to recruit. While Amy has her doubts about recruiting Knuckles, Sticks notes that she has never heard of Tails however.
Back in the Village Center, Eggman is disappointed about Morpho's performance. In response, Morpho wants to prove himself by convincing everyone at Meh Burger that he is the real Sonic. However, Morpho blows his cover when he orders a salad, which makes everyone at the restaurant recognize him while laughing at him, much to Eggman's bemusement. Meanwhile, Sonic, Amy and Sticks find Knuckles at the TV station. After receiving an autograph from Knuckles, Sonic states their wish to recruit him, which makes Knuckles laugh and mock their attempt to overthrow Lord Eggman. Still, Knuckles states that he would join them if they were more physically fit, which prompts Sonic to give him a challenge: if he beats him in a race to Gourmet Burger, he will join the Rebellion. Knuckles agrees to the terms, only for Sonic to win the race in a second (and come back with a plate of Gourmet Burgers).
Later at Lord Eggman's Lair, Sonic voices his disappointment to his new team about how he wanted to find Tails before coming to the lair. Sticks insists that they must strike back at Lord Eggman now before he becomes too powerful and has the crew climb to the top of the lair. There, they find this reality's Tails working on some Scorpion Bots. Sonic thinks Tails is in need of a rescue, only for Tails to reveal that he works for Lord Eggman as his (self-proclaimed) sidekick, which disappoints Sticks. Before Sonic can explain though, Tails alerts Lord Eggman. Sonic tells Tails to join their escape attempt, but Tails refuses on the grounds that he does not know him. This prompts Sonic to voice some personal facts about him, which leaves Tails stunned. Lord Eggman then arrives in Eggmobile and has his Scorpion Bots attack Team Sonic. As the crew overpowers his robots, Lord Eggman tries to fire his Eggmobile's missile at Team Sonic, only for Tails to stand in the way. Deciding that Tails is disposable, Lord Eggman fires his missile anyway, only for Sonic to save Tails and Sticks to dodge the missile. Confused, Tails asks Sonic why he would save his enemy, to which Sonic explains that even if they are on opposite sides, the Tails he knew would do the same for him. Moved by Sonic's faith in him, Tails joins Team Sonic. The whole team then delivers one final attack on Lord Eggman that sends him flying into the sky.
Back on Seaside Island, Sonic, now onboard his racecar, is ready to go home, although not before telling his alternate crew that with their help and Sticks' leadership, the Rebellion will soon overthrow Lord Eggman's rule. Tails then opens a portal to Sonic's dimension with a device, which Sonic enters while his friends say goodbye. At Meh Burger soon after, Eggman plays director while working on Morpho's emulation of Sonic. However, the villains get a surprise when Sonic shows up with his team. After receiving a good beating from the heroes, Eggman and Morpho retreat to Mombot, who is proud of how well her boys managed to work together despite their plan's failure, to recover.
- Mombot, a robot Dr. Eggman made in "Mombot", makes a reappearance.
- Morpho is still an associate of Dr. Eggman as a result of the events in "Eggman's Brother"; both villains even recall the events of said episode.
- Sonic and Knuckles have the cars they made in "If You Build It They Will Race".
- Eggman mentions to Morpho that one of the things on their to-do list was not to send Sonic to a dimension where there is another version of him, which would eventually cause the destruction of both dimensions; this nearly happened when an alternate-dimension Knuckles appeared in "Two Good to Be True".
- Amy recalls Morpho's deceit in "Eggman's Brother".
- In "Eggman: The Video Game Part 2: The End of the World", Lord Eggman would be plotting his revenge against Sonic for the humiliating defeat the hedgehog dealt him in this episode.
- When Knuckles advertises for his gym in his dimension, the sky shown in the background during his commercial is blue, like in the Sonic Boom World, instead of purple.
- In this episode, Lady Goat's fur has the same color it had during season one of the Sonic Boom television series.
Title in other languages
|French||Où sont allés tous les sonics||Where did all the Sonics go|
- Eight days before this episode aired on Boomerang, Bill Freiberger released the title card for this episode on Twitter as a teaser.
- Excluding himself, all the characters Morpho morphs into at Mombot's are the Sonic Boom incarnations of the main cast from the Sonic the Hedgehog video games.
- This scene might be a nod to the fans' demands for more Sonic video game characters to appear in the TV series.
- The title of this episode is a parody of the name for the modern folk-style song "Where Have All the Flowers Gone?".
- Sonic's quote "A shortcut to main street hidden in the canyon? Sweet easter egg" is a reference to the common Easter egg trope in modern media.
- Morpho states two famous catchphrases in this episode:
- Knuckles calls Sonic "Mr. Needlemouse", a reference to what Sonic was originally named in his early conception.
- The background music that plays when Sonic returns to his dimension is similar to the main theme for the Back to the Future franchise.
- Tails and Sticks do not have a single line of dialogue in this episode (not including their alternate counterparts).
- ↑ 1.0 1.1 Bill Freiberger on Twitter. Twitter (10 August 2017). Retrieved on 11 August 2017. “Bill Freiberger: Don't have a preview yet for episode 243 "Where Have All The Sonic's Gone" but I can tell you it was Written By: Marine & Cedric Lachenaud.”
- ↑ 2.0 2.1 Sonic Boom: Where Have All the Sonics Gone?. Zap2it.com. Retrieved on 29 July 2017.
- ↑ Bill Freiberger on Twitter. Twitter (17 August 2017). Retrieved on 17 August 2017. “Bill Freiberger: 246: Morpho sends Sonic to a dimension where he never existed. Sonic must unite his gang and help take back the alternate dimension village.”
- ↑ Bill Freiberger on Twitter. Twitter (11 August 2017). Retrieved on 11 August 2017. “Bill Freiberger: A little late, but here it is - the title card for Episode 243 "Where Have All The Sonic's Gone" written By: Marine & Cedric Lachenaud.”