Going after the seven legendary stones, the "Chaos Emerald", Sonic and friends continue to fight the evil genius professor Dr. Eggman.
The moment Sonic entered Eggman's headquarters, the seven Chaos emeralds gathered and created a large "Chaos Control", which blew Sonic and the others through time into the human world. There, Sonic met a kind boy, Chris... All of them were separated in an unknown world.
Will they be able to reunite? And what will happen to Eggman's world domination plan... ?