The Kingdom of Acorn, based within the city of Mobotropolis, was at war with an unseen enemy. The King recruited a human scientist, Julian, to build war machines to end the war with a victory. However, during peactime, Julian and his nephew Snivley launched a coup de'etat against the kingdom. The king is banished to another dimension, the Void, and the citizens are captured and transformed into robot slaves, through a machine called he roboticizer. Julian renames himself as Dr. Robotnik, now the rutlhless dictator of Mobius. Mobotropolis is renamed Robotropolis a polluted, industrial cityscape. Sonic uses a Power Ring to restore Uncle Chuck's free will in his mechanical body. Chuck decides to act as a spy for the freedom fighters, operating from within the city.
