Sonic battles the ancient, evil Mammoth Mogul - who has lost his Chaos Emerald and been imprisoned, but backing him into such a corner only made him more dangerous. Mogul uses his remaining powers to summon a new Fearsome Foursome - and Sonic is forced to be one of them. Every mercenary and cut-throat is hired to take Sonic's shoes - feet being optional. It's Sonic versus everyone else while the malicious mammoth laughs from the shadows. How can Sonic overcome all the odds?