Over 20 years ago, Doctor Eggman had finally completed his ultimate scheme to kill Sonic the Hedgehog, as well as the rest of his allies and rivals. And he succeeded. Shortly after, however, Eggman's fleet of Emerl robots had overrun him somehow on their own will, and eliminated him, as well.



According to rumor, Eggman had killed himself along with the heroes of Mobius, and as a result, the world was finally at peace, though the heroes were mourned for.

The story begins on Mobius, when Felix, Meteor, and Zelda are all going to celebrate their move in to the city named Celestia at a camp fire. When they're attacked by an army of robots with control over themselves, everything falls apart, and Felix starts to learn everything about the past, and has to find and venture "Into the Abyss" - to travel back into the past and correct the destroyed future he'll soon have.