Sonic the 3D Hedgehog: Under the World is an animated, 45 minute long movie starring characters from the Sonic the Hedgehog universe and more, taking place in the alternate universe sub-series, Sonic the 3D Hedgehog by Fusion Thunder Games. The film was created by Fusion Thunder as a promotional video to build excitement for the third installment of the series, Sonic the 3D Hedgehog: Guardians of Future Yet to Come. The film was released directly to DVD on November 9, 2013.


The film opens up on a summary of the ending events of Sonic the 3D Hedgehog: One World for All, where Sonic the Hedgehog, Miles "Tails" Prower, Amy Rose, Knuckles the Echidna and Tiara Boobowski defeat the omnipotent crystal form of Rouge the Bat and destroy the Atmostroyer, followed by the outcome of the fight, where Rouge goes to jail, comes out a nicer person a month later, Tiara and Sonic share a kiss, Dr. Eggman prepares a Chaos Emerald powered machine and Ogarate emerges out of the wreckage of Rouge's old base, Malice HQ, and the ruins of a giant Rouge robot.

Cut to the present day, Sonic, Tails and Amy are looking at a radar detecting a strange energy reading. Tails believes that it's a reading of Chaos Energy. Amy and Sonic think that it's coming from an Emerald, as in one of the 7 Chaos Emeralds, but Tails looks a closer look at the radar and sees that it's picking up something related to the Chaos Force, but it's not the same as the other Emeralds. The investigation begins as they walk out into the field, following the signal.

Meanwhile, Dr. Eggman is showing off his latest invention, the Egg Eater, a machine that will eat away at the crust of Mobius and make space for a "hive of chaos" in the doctor's name. A shadow flies above his head and a clanging noise is heard on top of the Egg Eater. It's Rouge, and she taunts Eggman and his robot soldiers as they look up. Eggman orders his minions to shoot her down, but she dodges all the ammunition they launch at her. She kicks down all of the robots and grounds Eggman, saying that she'll just take all the Emeralds and leave without hurting him, if Eggman is willing to behave. Soon enough, a robot with a laser gun shoots Rouge in the back, and she falls down next to Eggman. Eggman tells all of his remaining minions to start up the Egg Eater, but before any action can be taken, Rouge gets up and smirks at Eggman. Bewildered, Eggman holds up a blaster and points at Rouge. Her wings and arms begin to glow a blue colour, and her irises do the same before she unleashes two big lasers from her eyeballs, frying the bad doctor and the last of his robots. She turns around to face the Egg Eater and unleashes another pair of laser beams at the big machine, but the blast deflects off the Egg Eater's body and redirects the lasers to other places. The two laser make firework-like explosions in the air. One of them catches the eye of Tiara, who is in the middle of crafting a ring on North Island, while the other one is seen by Ogarate from Murtopia. The massive evil ogre gets an idea. Both of the explosions are seen by Sonic and his two pals, but they aren't bothered by it. Discovering the durability of the machine, Rouge decides that she won't let this technological achievement go to waste and takes command of it, claiming the Chaos Emeralds as her own in the process.

Tiara, after seeing the laser firework blast in the sky, is riding off to South Island on a ring-powered Motor Boat. Once she gets there, a giant, blacked-out monster with smoke coming out of it's mouth appears right in front of her. She outsmarts it, however, and gets away, but she falls into a hole, leading to the underworld of South Island, away from the beast. Her crystal blade begins to glow and point a thin stream of light in the direction she is facing. She follows the light, wondering if her blade has picked up a signal. A figure in the shadows on a cliff made of steel is watching over her. The figure recognizes the figure as Tiara, the manx girl from North Island, and the figure comes out of the dark, revealing himself to be Mighty the Armadillo.

Sonic, Tails and Amy look at the radar and find that it's detecting the source of the energy they've been trying to find. To find out what the radar has been bleeping about, they start digging, but only a few seconds later, a person covered in a black veil comes out of the ground, surprising everyone. The character wonders if the trio is looking for "The Chest", to which they reply by saying they have no idea what it's talking about. Sonic and Tails get curious and decided to explore the tunnel made by the stranger, leaving Amy behind. The mysterious character tells Amy that they should catch up in case the two boys get themselves into a lot of unexpected peril.

Tiara explores the ominous tunnel for a minutes on end, until she comes across a giant, golden door. She reaches for the doorknob and tries to open it, but finds that it's totally locked. Knowing that she'll have to get past it, she breaks it down with her Crystal Blade and goes straight in. On the other side, there's a large cave with a lava pit, two small stone huts and a giant keyhole at the top of a two story climb. Tiara looks at her weapon and sees the light pointing at the keyhole.

More story will be added later...


  • Roger Craig Smith as Sonic the Hedgehog
  • Kate Higgins as Miles "Tails" Prower
  • Cindy Robinson as Amy Rose
  • Michelle Ruff as Tiara Boobowski
  • Karen Strassmen as Rouge the Bat
  • Mike Pollock as Dr. Ivo "Eggman' Robotnik
  • J.B. Blanc as Ogarate
  • Johnny Yong Bosch as Mighty the Armadillo
  • Troy Baker as the Mysterious Hero
  • Michael McConnohie as the Mysterious Villain


  • This is the first film in the Sonic the 3D Hedgehog series, and it may possibly be the only one.
  • Death in this movie is always displayed on-screen, but it never gets way too graphic.
  • Tiara's weapon, the Crystal Blade, is at it's most powerful in this movie.
  • Sonic, Tails and Amy use their modern designs in this film, despite having their original designs (but with coloured eyes) in Sonic the 3D Hedgehog: One World by All, and the fact that this takes place shortly after that game. This may just be a foreshadowing of them using their modern designs in Sonic the 3D Hedgehog: Guardians of Future Yet to Come, though.