Illusion Island, a mysterious island that is set to appear once every decade in Sonic's world. Many eons ago, it was rumored to have a meteorite of extreme power crash into the island, bringing the force of a mysterious essence.
Outside of that, its origins are a mystery, and no one is certain of its existence. Most of the island's mysteries lie down to its nature; from the different kinds of fauna never seen anywhere else, to even its surrounding water holding a different reflection of what is actually present.
Due to its mysteriously rare appearance, the island went largely undocumented, and it would remain that way for a while. It would have stayed this way, until a certain Egg-shaped menace would choose to unravel the mysteries, and disturb the peace!
After the destruction of the Death Egg in Sonic 3 & Knuckles, as well as the Atomic Destroyer in Sonic Triple Trouble, Sonic, Tails and Knuckles celebrated their victory! Seeing as there would not be much for them to do, they all went their ways for an extended break, to relax. However, Dr Eggman's schemes were far from finished.
In the desperate searches of looking for a way to restore his practically destroyed army, his energy scanner picked up a mysterious power signature never seen before, coming from a location quite far from his base. A location of mystery; where the legendary Illusion Island was said to appear once every decade. Searching through his archives and books, while lacking information, Eggman had discovered that a meteor was said to have crashed there many eons ago. Also hearing that the meteor had contained tons of energy with mysterious force, the potential of utilizing such a tool would be great.
Eggman eventually took off to check it out for himself. Looking unto the meteor and its power, it was far beyond anything he had encountered before... and just what he needed to rebuild his army. Allowing him to build things twice as fast as he could ever with normal tools, just as efficiently and strong, Eggman had realized he found himself the greatest treasure yet! By this time, Sonic was becoming increasingly suspicious of Eggman's apparent disappearance. It wasn't until rumors of Illusion Island's reappearance and strange activity reached him that he knew that eggy-fellow was up to no good!
Sonic and his crew immediately left their break to see what Eggman was truly up to. They wouldn't know it until arrival, but they would have help to this task by a character who had spent his life on the island, and felt something wasn't right with Eggman's influence taking over slowly.
Only the seven Galactic Gems scattered mysteriously across the island are capable of nullifying the Doctor's strong and seemingly unlimited power source. Sonic and co. must collect them to take a stand to Eggman's plans. Without them, Eggman's army of badniks will once again expand and threaten the entire world.
Go Sonic, Hurry! The fate of the world is depending on you!
