As Sonic begins to chow chili dogs for a snack, he finds a message in the sack from his mother urging him to head to Speedster Island.
The Hedgehogs congregate on the Floating Island in their latest effort to find their mother. But Sleet and Dingo also have an interest in this island.
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 and The Freedom Fighters take out Robotnik's main computer, they're trapped by Swat-Bots in an underground tunnel, only to be rescued by a handsome teenager named Griff. Griff takes them deep beneath the Big City.
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.
Sonic conquers Robotnik's latest evil - a vehicle designated to locate and destroy living tissue matter - during a solo mission to the Badlands. Upon Sonic's return, the Freedom Fighters honor him with a victory party.
While on a mission to the big city to replace Nicole's malfunctioning microchip, Sonic and Sally encounter the Guardian, a mysterious cloaked figure who guards a dormant wizard named Lazar and his computer of evil spells.
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.
Sonic and the Freedom Fighters journey to Robotnik's lab in hopes of deciphering his roboti-sizer system. While underground, Sonic spots his now roboti-sized Uncle Chuck aboard a Badlands bound mine-train and devises a plan for his rescue.
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".
Sonia discovers that the watch she received from her friend is actually a monitoring device for the Robotnik Intelligence Agency.
A speed enhancing fluid deemed Sonic Tonic is created by Robotnik to make him as fast as Sonic so that he may finally catch him.
Robotnik has his eyes set upon Queen Aleena's crown jewel, but Sonic, Manic and Sonia plan to retrieve the gem before Robotnik.
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 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.
Sonic conquers Robotnik's latest evil - a vehicle designated to locate and destroy living tissue matter - during a solo mission to the Badlands. Upon Sonic's return, the Freedom Fighters honor him with a victory party.
Sonic is hired into an obvious trap when a frustrated Robotnik decides to appeal to the Hedgehog's ego and announces a "race to determine the fastest on Mobius".
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.