After obtaining the Blue and White Chaos Emeralds from Windy Valley and Casinopolis, Sonic and Tails are ambushed by Eggman, who steals one of the gems before escaping. Knuckles, meanwhile, finds more Master Emerald shards in Casinopolis and has a strange vision of an ancient Echidna tribe. After the vision, Knuckles confronts Eggman at the Station Square hotel and has to fight Chaos 2.
Following the battle, Eggman tells Knuckles that Sonic is also collecting Master Emerald shards, and our red hero decides to find Sonic for some answers. Meanwhile, Sonic and Tails have taken off to the Icecap Zone to find the Green Chaos Emerald. After a confrontation with Knuckles, Eggman again arrives to steal the emeralds and Sonic has to contend with the powerful Chaos 4...
