According to Knuckles, if this ice network was destroyed, Planet Freedom's rotation would hurl the Land of the Sky into outer space, killing everyone on it.

The Land of Darkness is the actual surface of Planet Freedom, a post-apocalyptic wilderness with the dastardly Ivo Robotnik as its sole living inhabitant.

After giving exposition of how Planet Freedom works (explaining the two "dimensions" of the planet, The Land of the Sky, and The Land of Darkness), Robotnik explains that a giant mecha named Metal Robotnik ("Black Eggman" in the original Japanese release) has exiled him from his utopian city of Robotropolis ("Eggmanland" in the original) and sabotaged the Robot Generator, which will explode by sunrise the next day.

After entering Robotropolis, Knuckles distracts the enemy robots while Sonic and Tails try to stop the generator in the heart of the city.

Sonic wakes up in Green Lake City and returns to the Presidential Palace, learning of Metal's goal from the President.

Sonic, Tails, and Knuckles go to the ice caps, where Sara is being held hostage by Robotnik, planning to marry her so the two will rule over Planet Freedom after the Land of the Sky's decimation.

The OVA series was produced by Studio Pierrot, Sega Enterprises and General Entertainment under the supervision of Sonic Team, Yuji Naka and Naoto Ohshima.

It is directed and storyboarded by Kazutaka Ikegami, with Mayori Sekijima handling the story structure, Masashi Kubota writing the scripts, Tsuneo Ninomiya designing the characters and Mitsuhiro Tada composing the music.

The OVA was originally distributed by Taki Corporation in Japan on a rental-only basis between January 26 and March 22 before being released for retail sale on May 31, 1996.

[7] The March 1996 issue of the DieHard Magazine gave the OVA a positive review stating that "all in all, the artwork looks amazing, plus it's an O.V.A., so the artists have been given quite an extensive budget.

[9] Chris Shepard of Anime News Network praised the OVA for its non-traditional action and said it was "good for Sonic fans".

[12] The Sonic the Hedgehog Archie Comics series contained various references to the OVA; in issue #101 the character Metal Robotnik appears in an alternate universe story, although his coloring altered from red to blue.