Sally, Rotor, Bunnie and Antoine take off in a homemade airplane, bound for an ancient city hidden deep in the Great Mountains, while Sonic follows via his favorite transportation, his sneakers.
When Sally uncovers Robotnik's plan to seed the cloud with toxic rain, they attempt a daring mission to sabotage the dirigible-like craft being transported by land vehicles. Mission fails when Sally, Bunnie and Antoine are captured.
When Robotnik launches a spy-orb that will uncover the Freedom Fighter's Knothole location, Sonic and Robot launch themselves up to the orbiting spy-sphere aboard a home-made rocket powered by Robotnik's discarded booster engine.
Robotnik severely upsets the ecosystem above and below the surface, when he sends explosive, Robotnik snake probes drilling deep under ground in search of oil lakes.
After Sonic is almost sucked inside the Void, he finds a huge Ring which Sally believes is an ancient relic but it turns out to be trick of the Sorcerer, Nagus. Sally and Bunnie are drawn inside the Void and when Sonic comes to rescue them.
Santa Claus has made an announcement - he is retiring and has picked the perfect successor - "Robotnikclaus"! Sonic and his sister resolve to persuade Santa to return and set Christmas straight. When the two track down the Santa who made the announcement, they discover he is just a phony robot and the real Santa Claus is being held prisoner.
When Sonic rescues a village from a flash flood, he's left with the job of babysitting three baby Groundhogs.
Robotnik learns that the most powerful gemstone -- able to create life itself -- is located in Prehistoric Times.
Robotnik timetravels back to Mobigypt, makes himself a pharoah, and enslaves everbody in an effort to find the gemstone of immortality.
Robotnik goes back to medieval times, and enlists the help of Merlink the Magician to get his gemstone.
When outlaws chase a sheriff out of a western town, Sonic takes over. But the outlaws are robots built by Robotnik. And when they capture a pretty possum of a saloon girl, Sonic meets Robotnik for a showdown.
When Robotnik puts a meteor on a collision course with a village, Sonic is forced to compete in the Robolympics to save the village. After a series of wild, booby trapped events, Sonic is victorious.
Coconuts inadvertantly creates a "super power" formula, when his janitor bucket spills in the lab. Robotnik falls into it and becomes "Super Robotnik", then challenges Sonic to a fight, with all of Mobius as the stakes. With Prof. Von...
Sonic and Tails help out an Owl/Chilidog Diner owner, named Bert Whoo, when Robotnik uses his henchbots to try to collect protection money. When the henchbots prove to be no match for Sonic.
A captain of the Queen's guard is captured before he can reach the secret rendezvous where he was to meet Queen Aleena.
Robotnik announces that he will marry Queen Aleena in a plot to become the king of Mobius.
Sonic, Manic and Sonia find an abandoned baby in an alley and begin to look for the baby's parents. Manic becomes very fond of the child.
Santa Claus has made an announcement - he is retiring and has picked the perfect successor - "Robotnikclaus"! Sonic and his sister resolve to persuade Santa to return and set Christmas straight. When the two track down the Santa who made the announcement, they discover he is just a phony robot and the real Santa Claus is being held prisoner.
During a mission to one of Robotnik's factories, Sally is taken prisoner by Robotnik and Snively, who construct a roboti-sized "Sally" clone, complete with Sally's personality, and mannerisms. The double tricks Sonic into rescuing "Sally".
Sonic and The Freedom Fighters journey to Robotnik's underground air base in a mission to reprogram the launch data on Robotnik's fleet of Stealth-Bot aircraft. While attempting to reprogram the Stealth-Bot computer system.