A homecoming is interrupted for Sonic, Sonia and Manic when Sleet and Dingo arrive to collect back taxes after returning to their birthplace.
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.
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".
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.
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.
Bob and the gang have got a big job on - repairing some pipework in Farmer Pickles field. / Bob, Scoop & Muck have to make repairs to a tunnel. When they arrive on site, Bob sends Muck ahead into the tunnel with a load of bricks.
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.
Robotnik's momma escapes from the home for mothers of villains and demands her birthday present! When she endangers Sonic and Tails, and they manage to have her taken back to the home, even Robotnik is glad to see her go.
When Tails gets trapped in the "Warp of Confusion" (an Escher-like world of another dimension) by Robotnik's cousin, Dr. Warpnik, Sonic comes to the rescue and traps Robotnik and his badniks in the warp.
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.
The Hedgehogs find out that Sonia has inherited a castle. She basks in the idea of having a castle for headquarters.
Rumor has it that Queen Aleena's journals are buried in the city of Tashistan. Sonic and his siblings search the city for the scrolls.
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 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 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".