Scourge the Hedgehog, Sonic's evil twin, is on the attack! Leading the Antiverse in a full-scale invasion, Scourge's goal is none other than multiversal domination - but will it happen with Sonic at his side? Not to be left out of the melee, Dr. Eggman has joined the fight with metal Sonic and a brand-new metal Scourge by his side! Is the battle over before it even begins? And what will Sonic's answer be to Scourge's offer of conquest?