Sonic Underground: Secrets of the Chaos Emerald (2008)
Secrets of the Chaos Emerald focuses on Sonic, Manic and Sonia as they help Knuckles, Floating Island's stern guardian of the Chaos Emerald, protect the Chaos Emerald from Dr. Robotnik and his henchmen, Sleet and Dingo. If the Chaos Emerald gets into the wrong hands it can be used as a weapon agains