After Sonic's newfound victory, he sets off on his biplane the "Tornado" in search of new places. He crashes lands on an island called West Side Island, where he is immediately attacked by a bunch of badniks and SWATBots. He is rescued by a young fox named Miles Prower, who he nicknames Tails due to him having twin tails. Tails lives with a bunch of other Mobians hiding out in Knothole Village. Sonic finds out that West Side Island is one of the islands that Robotnik took over. His birthplace Christmas Island being one of them. Sonic realizes that he lost the emeralds in the ambush and that there's a 7th Emerald. Can Sonic once again combat Robotnik and save another island?
