Sonic: The Neo Realms is a Sonic-series fan game created by JudgmentTH with the RPG Maker 2003 engine. So far, no story hasn't been shown yet, but a demo is expected to be released during summer/fall 2010.
Story[]
So far, the only story is that Knuckles is knocked down by Dr. Ivo "Eggman" Robotnik, and Sonic enters in time before Eggman can steal the Master Emerald.