Caught by Tails in the Tornado just after the events of Sonic 2, Sonic spots a strange island topped with a metal ring hovering near its snowy peak. Investigation leads to a confrontation with a Tails-shaped robot—a trap—and Eggman seizes the moment to steal the Chaos Emeralds. Tails knocks them into the Special Zone before Eggman can grab them, and the chase continues to Storm Station Zone.