S.O.N.I.C.X. ù the secret Sonic-hating organization ù is at it again! They have a special serum that will turn Sonic into the monster they think he ""really is."" The problem now is: how do you catch the fastest thing alive? It's a high-speed chase through the city with a special guest appearance by the Chaotix ù and an ending so big you won't believe it!