The evil scientist Dr. Robotnik has unleashed his most diabolical plot yet to turn the animals of planet Mobius into robots. His monstrous contraption, the Veg-O-Fortress, built on Mt. Mobius, is already transforming happy creatures into mindless slaves!

Robotnik's fiendish machine draws it's power from the mountain's volcano. Fiery lava fuels the lethal Pinball Defence System that protects the fortress.

Sonic and Tails mount an air assault on the fortress, only to be blasted in mid-flight by Robotnik's cannons. Sonic is knocked into the deep waters near the volcano. But he has friends in wet places -- and is saved at the last moment!

Sonic sneaks into the Toxic Caves below the fortress. From there, he infiltrates Robotnik's vast and deadly defences. In no time at all, Sonic starts swiping Emeralds, freeing the animals of Mobius and dishing out Hedgehog justice!

Yo, Robotnik! You're in for a mountain of trouble now. Sonic is spinning into action!